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Alzheimer disease. It is unclear if oral bacopa is beneficial in patients with Alzheimer disease. Details: A small clinical study in patients with Alzheimer disease or mild cognitive impairment shows that taking bacopa 300 mg daily for 12 months does not improve measures of cognitive function or memory when compared with donepezil or baseline measures (109623).
Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral bacopa is beneficial in children with ADHD. Details: A small clinical study in boys 6-14 years of age with symptoms consistent with ADHD but without an official diagnosis shows that taking a specific bacopa supplement (KeenMind - CDRI 08, Flordis) for 14 weeks does not improve symptoms of ADHD but improves some cognitive outcomes including error-making, cognitive flexibility, executive functioning, and sleep when compared with placebo. Bacopa 160 mg was given once daily in those weighing 20-35 kg and twice daily in those over 35 kg (109625). However, another small, open-label study in children aged 6-12 years with ADHD shows that taking a different bacopa supplement (BacoMind, Natural Remedies), 225 mg daily for 6 months, improves symptoms such as restlessness, impulsivity, learning problems, and attention deficit when compared to baseline (97603). The validity of these findings is limited by the lack of blinding or comparator group.
Back pain. Although there is interest in using oral bacopa for back pain, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Cognitive function. Bacopa seems to improve some measures of cognitive function, but data are conflicting. Details: A meta-analysis of 9 small clinical studies, along with more recent clinical research, shows that taking bacopa 300-600 mg daily for at least 12 weeks is not associated with improved measures of cognition including working memory, learning rate, recognition of pictures and words, reaction time, or attention when compared with placebo. However, subgroup analysis of this meta-analysis and another small clinical study show some evidence of improved reaction times, verbal learning, total recall, retention, memory, and information processing in healthy adults when compared with placebo (10058,17946,33287,97605,109624,111520). In children aged 6-8 years old, a very small clinical study shows that taking a syrup containing bacopa extract 350 mg three times daily for 3 months improves visual motor function and immediate memory when compared to baseline (33304). The validity of this finding is limited by the lack of a statistical comparison to the placebo group. Bacopa has also been studied in combination with other ingredients. A study in healthy adults aged 18-60 years shows that taking a single dose of a combination of bacopa 300 mg, American ginseng 100 mg, and coffee fruit extract 100 mg (Bacognize) improves some measures of working memory and attention by a small amount at 45 minutes when compared with placebo (103375). It is unclear if these effects are due to bacopa, other ingredients, or the combination. In contrast, a moderate-sized study in healthy, middle-aged adults shows that taking a combination product containing whole plant bacopa 7.5 grams, gingko biloba, and group B vitamins for 12 weeks does not improve measures of memory, attention, cognition, mood, or stress reactivity when compared with placebo. Subgroup analysis shows a possible benefit of bacopa supplementation on measures of attention in those with an optimal diet at baseline (111334).
Cognitive impairment. It is unclear if oral bacopa is beneficial in patients with cognitive impairment. Details: A small clinical study in patients with mild cognitive impairment or Alzheimer disease shows that taking bacopa 300 mg daily for 12 months does not improve measures of cognitive function or memory when compared with donepezil or baseline (109623).
Congestive heart failure (CHF). Although there is interest in using oral bacopa for CHF, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Depression. It is unclear if oral bacopa is beneficial in patients with depression. Details: Preliminary clinical research in adults with depression who have not responded to citalopram 40 mg daily shows that adding bacopa extract 300 mg twice daily for 4 weeks improves scores on depression rating scales when compared with citalopram alone (103378).
Hypertension. Although there is interest in using oral bacopa for hypertension, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Insomnia. Although there is interest in using oral bacopa for insomnia, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Irritable bowel syndrome (IBS). Bacopa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with diarrhea-predominant IBS shows that taking a combination of bacopa and bael (Aegel marmalos) reduces symptoms in 65% of patients, compared with 78% of patients taking clidinium bromide, chlordiazepoxide, and blond psyllium, and 33% taking placebo. Neither treatment is more effective than placebo for preventing relapses (10059).
Parkinson disease. It is unclear if oral bacopa is beneficial in patients with Parkinson disease. Details: A very small study in older adults with Parkinson disease taking levodopa shows that taking a specific bacopa extract (Cognitus, Herbarium) 225 mg or 450 mg daily for 90 days does not improve Parkinsonian or systemic symptoms, motor activity, emotional function, or social outcomes when compared with placebo (111523). The validity of these findings is limited by a small sample size and lack of randomization.
Rheumatoid arthritis (RA). Although there is interest in using oral bacopa for RA, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Sexual dysfunction. Although there is interest in using oral bacopa for sexual dysfunction, there is insufficient reliable information about the clinical effects of bacopa for this condition.
Smoking cessation. Oral bacopa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in adults with a history of smoking 5 or more cigarettes daily for at least 3 years shows that using a specific combination product containing bacopa 100 mg, ashwagandha, Indian gooseberry, tribulus, albizia lebbeck, licorice, clove, ginger, cowhage, holy basil, turmeric (Smotect , Smotect India) twice daily for 3 months reduces the number of cigarettes smoked daily and alveolar carbon monoxide and carboxyhemoglobin levels but does not improve lung capacity when compared with placebo (112115). It is unclear if these effects are due to bacopa, other ingredients, or the combination. More evidence is needed to rate bacopa for these uses.

GOTU KOLA

Burns. Topical gotu kola seems to improve the rate of burn healing. Details: Clinical research shows that applying a cream containing gotu kola 3% once daily to second degree burns increases the rate of re-epithelialization and complete healing by about 7 days when compared with silver sulfadiazine (SSD) 1% cream. Gotu kola cream also seems to reduce dryness, itching, irritation, and scar severity when compared with SSD (97027). Other research in adults with second degree burns shows that applying a gauze dressing containing gotu kola 5% and aloe 2.5%, covered with absorbent cotton wool and changed every 3 days, reduces time to healing by 1.5 days and length of hospital stay by 1.7 days when compared with the use of a gauze dressing containing chlorhexidine acetate 0.5% (97028).
Venous insufficiency. Oral gotu kola seems to improve symptoms of venous insufficiency. Details: Clinical research shows that taking gotu kola or a specific extract of gotu kola (Centellase) 60-180 mg daily orally for 4-8 weeks seems to improve measures of circulation and decrease symptoms such as edema in patients with venous insufficiency (6887,9786,11063,11064,11066,11070,52894,52909).

POSSIBLY INEFFECTIVE

Cognitive function. Oral gotu kola does not seem to be beneficial for cognitive function. Details: A meta-analysis of a small number of generally moderate quality clinical trials shows that taking a single dose of gotu kola, alone or in combination with other ingredients, does not improve cognitive function when compared with placebo (105334). In one study, gotu kola was taken in combination with ginkgo and docosahexaenoic acid (DHA) for 4 months by healthy, cognitively intact older adults (52880).
Radiation dermatitis. Topical gotu kola does not seem to reduce symptoms of radiation dermatitis. Details: Clinical research in females undergoing radiotherapy for breast cancer shows that applying a cream containing gotu kola extract 7% once daily during and up to 4 weeks following radiotherapy does not reduce the severity of dermatitis when compared with no treatment or applying a moisturizing cream (102792).

Aging skin. Oral gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in healthy, middle-aged females shows that applying a topical emulsion containing extracts of gotu kola 3% and Indian gooseberry 3% twice daily for 60 days improves skin hydration, some measures of skin wrinkles, and elasticity of the cheek (but not the eye) when compared with placebo (111571). It is unclear if these effects are due to gotu kola, Indian gooseberry, or the combination.
Alzheimer disease. Although there is interest in using oral gotu kola for Alzheimer disease, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Anal fissures. It is unclear if topical gotu kola is beneficial for anal fissures. Details: In patients with chronic anal fissures who are using standard dietary and hygiene treatments, preliminary clinical research shows that taking gotu kola extract 60 mg twice daily for 8 weeks and locally applying an ointment containing gotu kola does not reduce the mean time to bleeding cessation when compared with standard treatments alone. However, pain may be modestly improved. Also, gotu kola was less effective than an unspecified flavonoid mixture used both orally and topically (105332).
Atherosclerosis. It is unclear if oral gotu kola is beneficial for slowing the progression of atherosclerotic plaques. Details: Some preliminary clinical research shows that taking gotu kola extract 60 mg orally three times daily for 12 months helps stabilize low-density atherosclerotic plaques when compared with placebo (11062,11069). Gotu kola has also been evaluated in combination with a specific maritime pine bark product (Pycnogenol, Horphag Research). A non-randomized clinical trial shows that taking gotu kola 225 mg and Pycnogenol 150 mg in two divided doses daily for 3 months reduces plaque height and length and increases plaque echogenicity and stability when compared to control (97030). Another non-randomized clinical study in adults with atherosclerotic plaques and no other cardiovascular risk factors shows that taking gotu kola extract 100 mg and Pycnogenol 100 mg daily for up to 4 years reduces plaque progression and increases plaque echogenicity when compared with Pycnogenol alone or no treatment at all. Taking gotu kola and Pycnogenol is also associated with a reduced rate of clinical vascular events, including angina, myocardial infarction, minor transient ischemic attacks (TIAs), and minor strokes when compared with taking Pycnogenol alone or receiving no treatment at all (97029). It is unclear how these outcomes would compare to the use of gotu kola alone.
Attention deficit-hyperactivity disorder (ADHD). Although there is interest in using oral gotu kola for ADHD, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Atopic dermatitis (eczema). Topical gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying an ointment containing 5% each of the extracts of heart's ease, gotu kola, and Oregon grape twice daily for 4 weeks does not improve eczema when compared with a base cream. However, patients with eczema on skin exposed to cold weather might experience some improvement (67372).
Depression. Although there is interest in using oral gotu kola for depression, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Diabetic foot ulcers. Topical gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In patients with deep diabetic foot ulcers, preliminary clinical research shows that applying a cream (WH-1 cream) containing 1.25% of gotu kola and Plectranthus amboinicus extracts in a 4:1 ratio twice daily for 2 weeks after surgical debridement is as effective as the use of a standard hydrocolloid fiber wound dressing for improving wound size. However, when compared with baseline, changes in wound size were not statistically significant (105335).
Diabetic microangiopathy. It is unclear if oral gotu kola is beneficial for diabetic microangiopathy. Details: Preliminary clinical research shows that taking gotu kola extract 60 mg orally twice daily for 6-12 months helps increase measures of circulation and decrease edema in patients with diabetic microangiopathy (11065,11068,52917).
Dry skin. It is unclear if topical gotu kola is beneficial for dry skin. Details: In patients with dry skin associated with type 2 diabetes, clinical research shows that topical application with 0.25 grams of a gotu kola 1% ointment twice daily, either alone or with oral gotu kola 1100 mg twice daily, for 28 days does not improve dry skin when compared with placebo. However, in a sub-group of patients with well-controlled diabetes, the combination of oral and topical gotu kola modestly improved dry skin (105329). Additionally, a small clinical study in individuals with dry skin due to working with synthetic and natural dyes shows that application of a gotu kola 2% ceramide-based cream to the hands and arms twice daily for 4 weeks improves skin barrier hydration, as measured by hydration of the stratum corneum and skin acidity, when compared to baseline. These improvements were similar to those seen with a ceramide 5% cream (109554). As the gotu kola cream was formulated with ceramide, it is unclear if these findings are due to gotu kola, ceramide, or the combination.
Epilepsy. Although there is interest in using oral gotu kola for epilepsy, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Generalized anxiety disorder (GAD). It is unclear if oral gotu kola is beneficial for GAD. Details: In patients with GAD, preliminary clinical research shows that taking gotu kola extract 500 mg twice daily for 60 days reduces symptoms of anxiety, depression, and stress by 22% to 26% when compared with baseline (105333). The validity of these findings is limited by the lack of a comparator group.
Hemorrhoids. It is unclear if topical gotu kola is beneficial for hemorrhoids. Details: Preliminary clinical research in patients with chronic hemorrhoids, as well as patients with acute symptoms following a hemorrhoidectomy or surgical treatment for hemorrhoidal thrombosis, shows that taking gotu kola extract (Centella complex) 60 mg twice daily for 15 weeks and locally applying an ointment (Proctocella) containing gotu kola, arnica, and aloe, in conjunction with standard treatments, does not reduce the mean time to bleeding cessation when compared with standard treatments alone. Anal irritation was modestly improved in the patients with chronic hemorrhoids and in those undergoing treatment for hemorrhoidal thrombosis, but not in those that had undergone a hemorrhoidectomy (105336).
Herpes zoster (shingles). Although there is interest in using oral gotu kola for shingles, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Hypertension. It is unclear if oral gotu kola is beneficial for hypertension. Details: Preliminary clinical research in patients with hypertension shows that drinking a tea made by boiling gotu kola 4 grams in 250 mL water three times daily for 3 days modestly reduces systolic and diastolic blood pressure when compared with baseline. After consuming the tea, about 40% of patients had normal or high-normal systolic blood pressure and 77% had optimal or normal diastolic blood pressure, compared with 0% and 45%, respectively, prior to consumption (105330). The validity of these findings is limited by the lack of a comparator group.
Hypertrophic scars. Topical gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that topical use of a specific silicone gel (Bangkok Botanica) containing 15% extracts of gotu kola, onion, aloe, and paper mulberry, starting 2 weeks after surgery and continuing for 6 months, moderately improves the height and pliability of the post-surgical hypertrophic scar when compared with a silicone placebo gel. There was no effect on pigmentation or vascularity (102793). It is unknown whether any benefit is related to gotu kola, other ingredients, or their combination.
Idiopathic interstitial pneumonia. Oral gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small observational registry study in males less than 65 years old with idiopathic interstitial pneumonia has found that taking a specific gotu kola extract (Centellicum; Horphag Research) 225 mg three times daily in combination with a standardized extract of maritime pine bark (Pycnogenol, Horphag Research) 50 mg three times daily for 8 months is associated with a modest improvement in Karnofsky Performance Scale scores and a reduction in fatigue when compared with pirfenidone (108862). However, the validity of these findings is limited by the unblinded, non-randomized nature of the study.
Keloids. It is unclear if oral or topical gotu kola are beneficial for keloids. Details: There is some early evidence that applying a specific extract of gotu kola (Madecassol) topically might help reduce keloids and hypertrophic scarring (13558). Gotu kola has also been taken orally for keloids. Preliminary clinical research in patients at high risk for keloids shows that taking a specific extract of gotu kola (Centellicum, Horphag Research Ltd) 450 mg daily for 4 weeks starting on the second week after surgery seems to improve scar homogeneity and regularity (99756). However, the reliability of these results is limited because patients in this study were not randomized or blinded to different interventions.
Laser skin resurfacing. It is unclear if topical gotu kola is beneficial for recovery from laser skin resurfacing. Details: A small clinical trial shows that applying a gel containing gotu kola extract (ECa 233) 0.05% four times daily for 7 days, then twice daily for 3 months, improves wound healing following laser resurfacing for facial acne. Redness returned to baseline levels by day 7, in contrast to day 28 on the side treated with a placebo gel. The general wound appearance and crusting were also improved on the side on which the gotu kola extract gel was applied (102794).
Osteoarthritis. Topical gotu kola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large, single-blind clinical study in adults with knee osteoarthritis causing moderate pain shows that applying a specific cream (TMP-4) containing extracts of gotu kola leaf, sesame seed, soybean, and mangosteen peel four times daily for 4 weeks provides similar improvement in pain scores when compared with diclofenac 1% gel. Topical TMP-4 cream also seems to improve knee stiffness, stair climbing, and mobility similarly to diclofenac gel. However, patient impression of overall improvement was higher with diclofenac (110128). The validity of this study is limited by inadequate blinding.
Scarring. It is unclear if topical gotu kola is beneficial for scarring or tenderness from scarring. Details: Preliminary clinical research in patients without a history of keloid formation suggests that applying a specific cream (Alpha Centella, not available in the US) containing gotu kola and Bulbine frutescens extracts twice daily for 6-8 weeks following suture removal might help to reduce scarring (11072). Also, a large clinical study in adults who underwent carpal tunnel release surgery shows that applying gotu kola cream 1% three times daily for 6 months after suture removal marginally improves self-reported scar tenderness pain when compared with control, and modestly improves scarring scores when compared to baseline (112425). However, the interpretation of these findings is limited by patient-reported outcomes and insufficient validity of the scar scoring tool in this population.
Skin grafts. Although there is interest in using topical gotu kola for skin graft recovery, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Stretch marks (striae gravidarum). It is unclear if oral gotu kola is beneficial for stretch marks; topical gotu kola has only been evaluated in combination with other ingredients. Details: Preliminary clinical research in females with stretch marks shows that taking a specific extract of gotu kola (Centellicum, Horphag Research Ltd) 225 mg three times daily for 6 weeks increases skin thickness, elasticity, and perfusion when compared with a stretch mark minimizer cream (Clarins) and regular control cream (99757). The validity of these results is limited by the fact that patients were not randomized or blinded to the different interventions. Gotu kola has also been evaluated topically in combination with other ingredients. Preliminary clinical research shows that applying a specific mixture of gotu kola, vitamin E, and collagen-elastin hydrolysates in a cream (Trofolastin, not available in the US) daily during the second and third trimesters reduces stretch marks when compared with a placebo cream (13559). Another small clinical study shows that applying a specific mixture of gotu kola, vitamin E, essential fatty acids, hyaluronic acid, elastin, and menthol in an ointment (Verum, not available in the US) helps decrease the formation of stretch marks during pregnancy when compared with placebo (11073). Other preliminary clinical research in patients without previous striae shows that applying a specific formula containing hydroxyprolisilane C, rosehip oil, gotu kola triterpenes, and vitamin E (Velastisa Antiestrías, ISDIN) twice daily, beginning at week 10-14 and continuing throughout pregnancy, decreases the severity of both new and old stretch marks and the incidence of stretch marks when compared with placebo (92507). It is unclear if the effects seen in these studies are due to gotu kola, other ingredients, or the combinations.
Systemic lupus erythematosus (SLE). Although there is interest in using oral gotu kola for SLE, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Tonsillitis. Although there is interest in using oral gotu kola for tonsillitis, there is insufficient reliable information about the clinical effects of gotu kola for this condition.
Venous thromboembolism (VTE). It is unclear if oral gotu kola is beneficial for VTE prevention. Details: Preliminary clinical research shows that gotu kola decreases edema and improves measures of circulation in patients traveling on airplanes for more than 3 hours when compared to a control group receiving no treatment (11067). However, it is unknown if these changes reduce the incidence of clots.
Wound healing. Although there is interest in using topical gotu kola for wound healing, there is insufficient reliable information about the clinical effects of gotu kola for this purpose.
Wrinkled skin. It is unclear if topical gotu kola is beneficial for wrinkled skin. Details: Small, low-quality studies in healthy adults suggest that topical formulations of gotu kola extract or the constituent asiaticoside 0.1% or 0.2% applied 1-3 times daily have shown modest benefit for wrinkled skin. Cream or gel formulations were used for 12 weeks for periorbital wrinkles and a lipstick was used for 8 weeks for lip wrinkles. However, the extent of benefit is not clear and meta-analyses are limited to a very small number of studies with varied comparator groups, including placebo, vehicle, tretinoin 0.02%, and Pueraria mirifica extract (106639). More evidence is needed to rate gotu kola for these uses.

EFFECTIVE

Thiamine deficiency. Oral thiamine prevents and treats thiamine deficiency syndromes. Details: Thiamine deficiency is treated with oral thiamine 5-30 mg daily as a single dose or in divided daily doses for one month. For severe deficiency, thiamine up to 300 mg daily can be used (15).Thiamine deficiency can occur in people with malabsorption conditions such as alcohol use disorder, cirrhosis, and gastrointestinal diseases; in those with inadequate intake due to anorexia, nausea, and vomiting; and in those with increased requirements, including pregnancy, increased carbohydrate intake, increased physical activity, hyperthyroidism, infection, and liver disease. However, deficiency is rare with these conditions (15). The elderly might also be at increased risk for subclinical thiamine deficiency (11076).
Wernicke-Korsakoff syndrome (WKS). Parenteral thiamine is effective for treating symptoms of WKS. Details: Parenteral administration of thiamine 5-200 mg daily for 2 days decreases the risk of developing WKS and decreases symptoms of WKS in acute alcohol withdrawal. Between 30% and 80% of alcoholics are suspected to have thiamine deficiency (11075). An optimal dose for treating WKS has not been established; however, early research suggests that a 200 mg intramuscular dose may be more effective than lower doses (11075). In contrast, a moderate-sized clinical trial in adults with a history of heavy alcohol use who were asymptomatic or symptomatic for WKS shows that there is no benefit to administering high doses (300 mg 3 times daily) compared with medium (100 mg 3 times daily) or low (100 mg daily) doses of parenteral thiamine on cognitive or neurological functioning (111690). The study may have been inadequately powered to detect a difference between groups.

Dysmenorrhea. Oral thiamine might reduce pain in some patients with dysmenorrhea. Details: A clinical study in adolescent Iranian females with dysmenorrhea shows that taking thiamine 100 mg alone or along with fish oil 500 mg daily for 2 months moderately reduces pain intensity and duration when compared with placebo (89341). Another preliminary clinical study in Indian females 12-21 years of age with moderate to severe primary dysmenorrhea shows that taking thiamine 100 mg daily for 90 days eliminates pain in 87% of participants when compared to baseline (77820). The validity of this finding is limited by the lack of a placebo group. Furthermore, available research was conducted in India and Iran, so it is unclear if these findings are generalizable to other geographic locations.

POSSIBLY INEFFECTIVE

Coronary artery bypass graft (CABG) surgery. Intravenous thiamine does not seem to improve outcomes after CABG surgery. Details: A small clinical study in adults undergoing CABG surgery with cardiopulmonary bypass shows that giving intravenous thiamine 200 mg immediately prior to surgery and immediately after surgery does not improve clinical outcomes or lactate levels when compared with placebo (97010). Larger doses of thiamine also don't seem to be beneficial. Another small clinical study in patients receiving CABG with cardiopulmonary bypass shows that giving thiamine 600 mg intravenously on the day of surgery, and 400 mg daily for three postoperative days, does not improve postoperative outcomes when compared with placebo (103000).
Heart failure. Most research suggests that oral or intravenous thiamine does not improve outcomes in patients with heart failure. Details: Observational research suggests that having heart failure is associated with 2.5-fold increased odds of having thiamine deficiency, possibly because of diuretic use, intestinal malabsorption, and metabolism changes. However, it is unclear if thiamine supplementation is beneficial. A meta-analysis of 2 small clinical trials in adults with systolic heart failure and unclear thiamine status shows that thiamine 200-300 mg given orally or by IV for 7-28 days improves left ventricular ejection fraction (LVEF) by 3% when compared with control (97012). However, other meta-analyses and clinical studies in adults with heart failure with or without thiamine deficiency show that taking intravenous, intramuscular, or oral thiamine 100-500 mg daily does not improve LVEF fraction, left ventricular end-diastolic volume, dyspnea, mortality, hospitalization, or exercise tolerance when compared with placebo or control (103002,111682,111686,111688).
Mosquito repellent. Oral thiamine does not seem to repel mosquitos. Details: Clinical research in healthy volunteers shows that taking thiamine does not improve mosquito repellency when compared with taking vitamin C as a control (18016).
Sepsis. Intravenous or oral thiamine, alone or in combination with vitamin C and hydrocortisone, does not seem to reduce mortality or prevent organ failure in sepsis or septic shock. Details: Multiple meta-analyses of small clinical studies in patients with septic shock show that intravenous or oral thiamine 100-500 mg 2-3 times daily for 3-7 days is no better than placebo for improving mortality, end-organ damage, number of ventilator-free days, and duration of intensive care unit (ICU) stay (105443,107717,107727,111689). One meta-analysis suggests that administration of thiamine alone increases the risk of mortality in these patients (111689). Subgroup analyses including only higher quality studies also fail to show a benefit of thiamine (107717). Another recent small clinical trial in patients with septic shock shows that receiving the same dose of intravenous thiamine does not increase vasopressor-free days when compared with placebo (105441). Intravenous thiamine 200 mg every 12 hours has also been evaluated in combination with intravenous vitamin C 1.5-2 grams and hydrocortisone 50-200 mg every 6-12 hours for 4-10 days (HAT therapy). While some retrospective research found HAT therapy to be beneficial (100315,102980,111689), high-quality, prospective clinical research has shown no benefit (105447,109956,111689). Meta-analyses in patients with sepsis and septic shock shows that receiving HAT therapy does not improve mortality, kidney injury, number of ventilator-free days, or ICU length of stay when compared with control (102129,104027,104028,104032,102998,105447,109956,111642,111689). Additionally, the meta-analyses suggest that HAT therapy does not reverse shock or improve sequential organ failure assessment (SOFA) scores (109556,111642). However, one meta-analysis found that HAT therapy shortened the duration of vasopressor use when compared with placebo (111642). Long-term follow up from a study in patients with sepsis-induced respiratory and/or cardiovascular dysfunction shows that receiving HAT therapy does not improve cognitive, psychological, or functional status after 6 months and, for immediate memory scores and development of posttraumatic stress disorder, HAT therapy was less beneficial when compared with placebo (111299).

Acute kidney injury (AKI). It is unclear if oral or intravenous thiamine is beneficial for treating or preventing AKI. Details: Observational research in adults admitted to the intensive care unit (ICU) with AKI has found that treatment with thiamine (dose unspecified) within the first 48 hours of admission is associated with 39% lower odds of in-hospital mortality and 28% higher odds of kidney function recovery when compared with patients that did not receive thiamine. Receiving thiamine was also associated with a 0.5-day reduction in ICU length of stay (107719).
Anxiety. Although there is interest in using oral thiamine for anxiety, there is insufficient reliable information about the clinical effects of thiamine for this purpose.
Cardiac arrest. It is unclear if intravenous thiamine reduces the risk of death after resuscitation from cardiac arrest. Details: A small clinical study in adults resuscitated from cardiac arrest shows that receiving intravenous thiamine 100 mg every 8 hours for 7 days does not reduce 28-day mortality when compare with a normal saline placebo (105442).
Cardiovascular disease (CVD). It is unclear if oral thiamine is beneficial for treating or preventing CVD. Details: Population research in Korea has found that insufficient dietary thiamine intake (daily intake of less than 1.22 mg in males or 1.03 mg in females) is associated with a 16% increased odds of developing angina or myocardial infarction when compared with sufficient dietary thiamine. However, the effects of thiamine supplementation on CVD have not been studied (107725).
Cataracts. Small studies suggest that increased dietary thiamine might help prevent cataracts. Details: Observational research has found that a high dietary intake of thiamine 10 mg daily is associated with 40% lower odds of nuclear cataracts (6378). Other population research has found that higher dietary intake of thiamine is associated with a modestly reduced risk of age-related lens opacification (14301).
Cervical cancer. It is unclear if oral thiamine reduces the risk of developing cervical cancer. Details: Epidemiological research has found that increasing intake of thiamine from dietary and supplemental sources, along with folic acid, riboflavin, and vitamin B12, is associated with a lower odds of precancerous cervical lesions (11074).
Child development. It is unclear if supplementing breastfeeding females with oral thiamine improves infant neurocognitive development. Details: Preliminary clinical research shows that supplementing breastfeeding females with oral thiamine, 1.2-10 mg daily for 22 weeks, starting at 2 weeks postpartum, does not improve most cognitive or neurodevelopmental scores in the child when compared with placebo. However, one subgroup analysis suggests that thiamine supplementation may improve language scores (107726).
Cognitive function. Oral thiamine has only been studied in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in healthy, middle-aged adults shows that taking a combination product containing thiamine hydrochloride 50 mg, other group B vitamins, bacopa, and ginkgo daily for 12 weeks does not improve measures of memory, attention, cognition, mood, or stress reactivity when compared with placebo. Subgroup analysis shows a possible benefit of the combination supplementation on measures of attention in those with an optimal diet at baseline (111334). It is unclear if these findings are due to thiamine, other ingredients, or the combination.
Coronavirus disease 2019 (COVID-19). It is unclear if intravenous or oral thiamine improves clinical outcomes in patients hospitalized with COVID-19. Details: A small observational study of adults admitted to the intensive care unit with COVID-19 has found that treatment with intravenous or oral thiamine 100 mg daily for an average of 7 days is associated with a 63% reduction in the odds of death within 30 days when compared with control. However, there was no associated reduction in duration of hospitalization or mechanical ventilation (107721). In addition, a small observational study of adults with encephalopathy that were mechanically ventilated secondary to COVID-19 has found that taking thiamine 500 mg three times daily orally for 5 days improves neurological manifestations, including ophthalmoparesis and ataxia, when compared with baseline. The validity of this study is limited by the lack of a comparator group (107722).
Critical illness (trauma). It is unclear if oral or intravenous thiamine is beneficial in patients with critical illness. Details: A meta-analysis of critically ill patients shows that treatment with oral or intravenous thiamine 100-600 mg daily for up to 7 days does not affect the need for mechanical ventilation, duration of hospital stay, or mortality when compared with control (107727).
Delirium. It is unclear if oral or intravenous thiamine helps to prevent or treat delirium. Details: In critically ill patients, a meta-analysis of clinical research shows that treatment with oral or intravenous thiamine 100-600 mg daily for up to 7 days reduces the odds of developing delirium by 42% when compared with control (107727). However, some observational research in adults with septic shock has found that receiving intravenous thiamine 400 mg daily with vitamin C 6 grams daily, both in divided doses, is not associated with reduced delirium when compared with control (103001). In non-critically ill, hospitalized adults with altered mental status, retrospective, observational research has also found that administration of oral or intravenous thiamine is not associated with improved cognitive function or reduced in-hospital mortality when compared with control (107723). Preliminary clinical research in adults undergoing an allogeneic hematopoietic stem cell transplant also shows that administering thiamine 200 mg three times a day intravenously for 7 days does not prevent delirium or shorten duration of delirium when compared with placebo (107718).
Dementia. It is unclear if oral thiamine is beneficial for the prevention of dementia. Details: Observational research in patients with alcohol use disorder has found that taking thiamine is associated with a 24% to 46% lower risk of developing dementia when compared with not taking thiamine (102999).
Depression. It is unclear if oral thiamine is beneficial in patients with depression. Details: Meta-analyses of population research in adults has found that high dietary consumption of thiamine is associated with a 10% to 31% lower risk of having depression when compared with low dietary consumption of thiamine. However, this research did not evaluate the effects of thiamine supplementation on depression (107133,107725). One small clinical study in adults with major depressive disorder shows that taking thiamine 300 mg daily in conjunction with fluoxetine 20 mg daily leads to greater improvements in depressive symptoms at 6 weeks when compared to fluoxetine with placebo. This benefit was no longer present at 12 weeks. This suggests that thiamine may accelerate improvement in symptoms during initiation of fluoxetine therapy (97013).
Diabetes. It is unclear if oral thiamine is beneficial for type 2 diabetes or gestational diabetes. Details: A meta-analysis of 6 clinical studies in adults with type 2 diabetes shows that taking thiamine 100-300 mg or its derivative benfotiamine 120-900 mg daily for 1-3 months does not reduce glycated hemoglobin (HbA1c), fasting blood glucose, or postprandial blood glucose when compared with placebo (111681). A large, prospective cohort study in adults without type 2 diabetes suggests that the risk of new-onset diabetes is minimized in adults consuming thiamine 0.75-1.10 mg daily from the diet, while lower and higher thiamine intake levels are associated with an increased risk of new-onset diabetes (111685). Thiamine has also been studied for preventing gestational diabetes. A large, prospective cohort study in pregnant adults suggests that higher supplementation with thiamine during the first and second trimesters is associated with a lower risk of gestational diabetes when compared with lower levels of total thiamine intake. However, this effect was not found for dietary intake of thiamine, only supplementation. Additionally, the participants were mostly Han Chinese adults, limiting the generalizability of the findings to other populations (111680).
Diabetic nephropathy. It is unclear if oral thiamine is beneficial for diabetic nephropathy. Details: A small clinical study in patients with early-stage diabetic nephropathy and microalbuminuria shows that taking thiamine 100 mg three times daily for 3 months decreases urinary albumin excretion, but does not affect glomerular filtration rate (GFR), when compared with placebo (16556).
Diabetic neuropathy. Although there is interest in using oral thiamine for diabetic neuropathy, there is insufficient reliable information about the clinical effects of thiamine for this condition.
Dry eye. Oral thiamine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with dry eye suggests that adding unspecified doses of thiamine and mecobalamin to treatment with daily artificial tears and corticosteroid drops might slightly improve overall symptoms when compared with only artificial tears and corticosteroid drops for 1 month. There were no differences between groups at 2 months (105444). This finding is limited due to incomplete reporting and a lack of adjustment for multiple hypothesis testing.
Dyslipidemia. It is unclear if oral thiamine is beneficial for treating or preventing dyslipidemia. Details: A meta-analysis of 3 clinical studies in adults with type 2 diabetes shows that taking thiamine 100-300 mg or its derivative benfotiamine 120-900 mg daily for 1-3 months does not improve low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, or triglycerides when compared with placebo (111681). Observational research in Korea suggests that insufficient dietary thiamine intake (daily intake of less than 1.22 mg in males or 1.03 mg in females) is associated with 10% higher odds of developing dyslipidemia when compared with sufficient dietary thiamine intake. However, the effects of thiamine supplementation on dyslipidemia have not been studied (107725).
Emergence delirium. It is unclear if intravenous thiamine helps to prevent emergence delirium in patients after surgery. Details: One clinical study in adults in the intensive care unit (ICU) after gastrointestinal surgery shows that receiving intravenous thiamine 200 mg daily for 3 days is associated with up to 84% lower odds of emergence delirium on the first two days, but not on the third day, when compared with a normal saline control (105440).
Fatigue. It is unclear if oral thiamine is beneficial in patients with fatigue. Details: A small clinical crossover study in patients with chronic fatigue and inflammatory bowel disease (IBD) shows that taking thiamine 600-1800 mg daily for 20 days reduces fatigue scores when compared with placebo (105438). Taking oral thiamine 300 mg daily for an additional 12 weeks did not seem to affect fatigue scores when compared with placebo. However, an observational follow-up study found that those who self-continued thiamine for an additional 24 weeks after the study ended reported lower fatigue scores when compared with those who did not self-continue thiamine (107720).
Glaucoma. Although there is interest in using oral thiamine for glaucoma, there is insufficient reliable information about the clinical effects of thiamine for this condition.
Herpes zoster (shingles). It is unclear if subcutaneous thiamine is beneficial in patients with shingles. Details: A small clinical trial shows that receiving subcutaneous thiamine 100 mg injections six times weekly for 4 weeks reduces itching by at least 30% in 67% of patients with herpes zoster. However, thiamine does not appear to significantly reduce pain in most patients (90396).
Hypertension. It is unclear if oral thiamine is beneficial in treating or preventing hypertension. Details: Population research in Korea has found that insufficient dietary thiamine intake (daily intake of less than 1.22 mg in males or 1.03 mg in females) is associated with a 5% increased odds of developing hypertension when compared with sufficient dietary thiamine. However, the effects of thiamine supplementation on hypertension have not been studied (107725).
Impaired glucose tolerance (prediabetes). It is unclear if oral thiamine is beneficial in patients with prediabetes. Details: A very small clinical trial in patients with prediabetes shows that taking thiamine 100 mg by mouth three times daily for 6 weeks modestly decreases 2-hour postprandial plasma glucose levels when compared to baseline and decreases fasting blood glucose levels when compared with placebo (91168).
Kidney failure. Oral thiamine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary, low-quality, clinical research in adults with kidney failure undergoing regular hemodialysis shows that taking oral thiamine 90 mg daily with folic acid 30 mg daily for 96 weeks reduces overall mortality by 67% and improves cognitive scores by 31% when compared with no intervention (107724). It is unclear if this effect is due to thiamine, folic acid, or the combination.
Migraine headache. It is unclear if dietary thiamine is beneficial for the prevention or treatment of migraine headache. Details: A large, retrospective, cross-sectional study suggests that higher dietary intake of thiamine is associated with lower odds of severe headache or migraine, especially in females (111684). The validity of these effects is limited by the subjective outcome measures and retrospective study design.
Pneumonia. It is unclear if thiamine is beneficial for patients with pneumonia. Details: A large retrospective cohort study in adults hospitalized with pneumonia and active alcohol use disorder suggests that parenteral administration of thiamine is associated with reduced 14-day mortality and more frequent discharges home, but not a shorter length of stay or fewer ICU transfers, when compared with no thiamine use. Furthermore, parenteral thiamine doses above 200 mg do not appear to improve mortality but may be associated with longer length of stay and less frequent discharges home when compared with low oral doses of thiamine or parenteral thiamine at doses under 200 mg (111679). The validity of these effects is limited by the retrospective study design.
Ventilator-associated pneumonia (VAP). It is unclear if oral or parenteral thiamine is beneficial for patients with VAP. Details: A retrospective study in adults with VAP in the intensive care unit (ICU) suggests that supplementation with intravenous or oral thiamine may be associated with reduced ICU and in-hospital mortality (111683). The validity of these effects is limited by the retrospective study design. More evidence is needed to rate thiamine for these uses.

VALERIAN

Insomnia. Most research shows that taking valerian whole root extract 300-600 mg daily modestly improves subjective sleep quality, although it might take up to 4 weeks to provide benefit. Valerian does not seem to improve sleep latency, sleep duration, or insomnia severity. Details: Although there is a great deal of conflicting research, overall, taking valerian 300-600 mg before bedtime seems to improve sleep quality when compared with placebo. In contrast, no consistent benefit has been seen for sleep latency, sleep duration, or insomnia severity (15046,17577,19406,19409,104010). Older meta-analyses show that valerian root improves sleep quality regardless of its formulation. However, the most recent meta-analysis shows that valerian whole root extract improves sleep quality, while it's unclear whether an unspecified valerian extract is effective (17577,19406,104010). These analyses are limited by significant heterogeneity in valerian dosage and formulation, treatment duration, and included patient populations. Some experts claim that valerian does not work acutely for sleep, and it can take up to 4 weeks for a benefit to be seen (10209,104010). Indeed, most short-term studies assessing valerian as a single dose, or used daily for up to one week, show no benefit for sleep quality when compared with placebo (19407,19408,19411,19414). However, a meta-analysis of studies lasting 4 weeks or longer also did not find a consistent benefit (104010). The benefits of valerian for sleep might vary in different patient populations. A large post-marketing surveillance study in children with restlessness or dyssomnia under the age of 12 has found that taking a specific combination product (Euvegal Forte, Dr. Willmar Schwabe Pharmaceuticals) containing valerian root extract 160 mg and lemon balm extract 80 mg 1-2 tablets once or twice daily is associated with moderate sleep improvement (14416). Also, one clinical study in postmenopausal adults shows that taking valerian root extract 530 mg (Sadamine) twice daily for 28 days moderately improves sleep quality when compared with placebo (19425). Another clinical study in patients undergoing treatment for cancer shows that taking valerian 450 mg 1 hour before bedtime for 8 weeks does not improve objective sleep measures, but might improve subjective sleep ratings and mood, when compared with placebo (19424). Small clinical studies in adults on hemodialysis show that taking valerian 530 mg before bedtime for 1 month improves sleep quality when compared with baseline or placebo. (105718,110712). In one of these studies, improvements in sleep quality were similar when compared with gabapentin (110712). Research also shows that taking specific combination products containing valerian and other ingredients can improve sleep quality. These combination products have combined valerian with hops; lemon balm (Euvegal Forte); lemon balm and hops (Valerina Natt); or passionflower and hops (NSF-3, M/s Tablets India) (10423,15018,19413,19417,19418,19419,88193,89408). Finally, limited research has compared valerian to benzodiazepines. A small clinical study in patients with non-organic insomnia shows that taking valerian extract (LI 156, Sedonium) 600 mg daily for 6 weeks seems to be no different for improving sleep quality when compared with taking low-dose oxazepam 10 mg (19416). Valerian might also improve sleep quality in patients who are resistant to chronic benzodiazepine therapy. In one small study, after tapering the benzodiazepine over two weeks, valerian extract 100 mg three times daily for 15 days improves sleep quality when compared with placebo (8006).

Anxiety. It is unclear if valerian is beneficial for anxiety. Details: Meta-analyses of heterogeneous clinical research show that there is insufficient and contradictory evidence on the use of valerian root for anxiety (104010,110711). However, one analysis suggests that using whole root preparations seems to have greater efficacy than valerian extracts (104010). These meta-analyses are limited by significant heterogeneity in valerian dosage and formulation, treatment duration, and patient populations and concerns related to publication bias (104010,110711). One small clinical study in patients with generalized anxiety disorder (GAD) shows that taking valerian extract containing 81.3 mg valepotriates daily for 4 weeks is no different for reducing anxiety scores when compared with diazepam 6.5 mg or placebo (9896). This study was not adequately powered to detect a difference between groups. Also, a small, quasi-randomized trial in adults with poor sleep quality who are undergoing hemodialysis shows that taking a specific valerian root product (Sedamin, Goldaru Company) 530 mg daily for 1 month improves anxiety scores by 2-3.9 times when compared with placebo. However, not all patients reported anxiety at baseline (105718). In contrast, a small clinical study in healthy adults shows that taking a combination of herbal extracts containing valerian root, passionflower, ballota, and hawthorn (Euphytose) daily for 14 days reduces subjective anxiety and objective sympathetic and autonomic nervous system activation in response to a psychosocial stressor when compared with placebo (111222). It is unclear if these effects are due to valerian, other ingredients, or the combination.
Delirium. Oral valerian has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adult intensive care unit (ICU) patients with agitation and delirium receiving quetiapine 50-200 mg every 12 hours shows that taking 5 mL of syrup containing valerian root 625 mg and an extract of lemon balm leaf 50 mg every 12 hours improves agitation from baseline similarly to placebo. It is unclear if the improvement from baseline differed between groups (106627).
Depression. It is unclear if valerian is beneficial in patients with depression. Details: A retrospective case series in patients with mild to moderate depression and reports of anxiety has found that taking high-dose valerian 1000 mg with St. John's wort is associated with more rapidly improved depressive symptoms than low-dose valerian 500 mg with St. John's wort (19402). The validity of this study is limited by its retrospective nature and small size. Also, it is unclear if this effect is due to valerian, St. John's wort, or the combination. One small, quasi-randomized trial in adults with poor sleep quality who are undergoing hemodialysis shows that taking a specific valerian root product (Sedamin, Goldaru Company) 530 mg daily for 1 month improves depression scores by 2-3.9 times when compared with placebo. However, not all patients reported depression at baseline (105718).
Dysmenorrhea. One small study suggests that oral valerian may reduce symptoms of dysmenorrhea. Details: A small clinical study shows that taking powdered valerian root 255 mg three times daily for two menstrual cycles reduces pain severity associated with menstruation when compared with placebo (19342).
Menopausal symptoms. Two small studies suggest that oral valerian may reduce hot flashes. Details: Two small clinical studies in postmenopausal adults show that taking valerian root (Zardband or Goldaroo Co.) 225 mg three times daily or 530 mg twice daily for 2 months moderately reduces hot flash frequency and severity when compared with placebo (89407,96243). Both studies were conducted in Iran, so it is unclear if these results are generalizable to other geographic locations.
Premenstrual syndrome (PMS). One small study suggests that oral valerian may reduce PMS symptoms. Details: A small clinical study in young adults with PMS shows that taking valerian root extract (Goldaroo Co.) 530 mg twice daily on the last 7 days of the menstrual cycle for 3 cycles moderately reduces the severity of self-reported PMS symptoms when compared with placebo (96239).
Pre-procedural anxiety. One small study suggests that oral valerian may reduce anxiety during wisdom tooth extraction. Details: A small crossover clinical study in patients undergoing impacted mandibular molar extraction shows that taking valerian extract (Dermatologica Ltda.) 100 mg one hour prior to the extraction reduces physiological responses to anxiety to a satisfactory but lesser degree than midazolam 15 mg. Patients expressed no clear preference for either valerian or midazolam for reducing perioperative anxiety (102242). The validity of these findings is limited by the use of subjective outcome measures.
Restless legs syndrome (RLS). It is unclear if oral valerian is beneficial in patients with RLS. Details: A small clinical study in patients with RLS shows that taking valerian (Pharmavite, LLC) 800 mg daily for 8 weeks does not improve RLS symptoms or sleep latency when compared with placebo (19422). However, this study was not adequately powered to detect a difference in RLS symptoms between groups. Conversely, another small clinical study in adults with RLS on hemodialysis shows that taking valerian 530 mg nightly before bed for 1 month reduces symptoms of RLS when compared to baseline; however, valerian's effects were weaker when compared with gabapentin 100 mg nightly (110712). The validity of this study is limited by a lack of a placebo group and a small sample size.
Stress. Two small studies suggest that oral valerian may reduce the stress response in healthy adults who are performing a stressful mental task or a verbal presentation. Details: Two small clinical studies in healthy volunteers shows that taking valerian 100 mg once or 600 mg daily for 7 days prior to participating in a mental stress task or public verbal test reduces physiologic responses to stress and feelings of anxiety when compared to baseline (9893,9895). The validity of these findings is limited by the lack of statistical comparison to the control group. Another small study in healthy volunteers shows that taking a specific combination product containing valerian 360 mg and lemon balm 240 mg (Songha Night, Pharmaton Natural Health Products) reduces anxiety associated with laboratory-induced stress. However increasing the dose to valerian 1080 mg and lemon balm 720 mg seems to increase anxiety (19405).
Tension headache. One small study suggests that oral valerian may reduce tension headache. Details: A small clinical study in patients with frequent tension headaches shows that taking valerian root extract (Sedamin, Goldaru Pharmaceutical Company) 1060 mg daily after dinner for one month modestly reduces headache severity and disability when compared with placebo (103221). More evidence is needed to rate valerian for these uses.

VITAMIN B6

EFFECTIVE

Pyridoxine-dependent epilepsy. Intravenous vitamin B6 is effective for controlling pyridoxine-dependent seizures. Details: Pyridoxine-dependent seizures are a rare type of refractory seizures in neonates that do not respond to anticonvulsant drugs. These seizures are typically controlled within minutes of intravenous administration of pyridoxine, a form of vitamin B6. Pyridoxine-dependent seizures can be due to genetic (autosomal recessive) pyridoxine dependency, or more commonly, a result of the use of high-dose pyridoxine during pregnancy (8197,8198).
Sideroblastic anemia. Oral vitamin B6 is effective for treating hereditary sideroblastic anemia. Details: Taking vitamin B6 (pyridoxine) orally is effective for treating hereditary sideroblastic anemia (15,9518). Taking the active form of vitamin B6 (pyridoxal-5'-phosphate) also seems to be effective in cases in which the patient does not respond to pyridoxine (93049).
Vitamin B6 deficiency. Oral vitamin B6 is effective for preventing and treating vitamin B6 deficiency. Details: Taking oral vitamin B6 can prevent and treat vitamin B6 deficiency (15).

LIKELY EFFECTIVE

Hyperhomocysteinemia. Taking vitamin B6 orally, alone or in combination with folic acid, is effective for reducing hyperhomocysteinemia. Details: Vitamin B6 (pyridoxine) seems to lower homocysteine concentrations when folic acid and vitamin B12 are at physiologic levels or when given with folic acid and vitamin B12 supplements (9451,83042,107136). A combination of vitamin B6 100 mg and folic acid 0.5 mg daily seems to lower homocysteine levels by about 35% and is recommended for people with postprandial hyperhomocysteinemia (1489,9406). Other research shows that taking pyridoxine 50-200 mg daily reduces postprandial homocysteine levels by 32% to 35% (9406,10350). Pyridoxine also seems to reduce homocysteine levels in patients with kidney failure, kidney transplant patients (1489,6884,9414,9415), or patients who receive general anesthesia with nitrous oxide (9481). However, some research in healthy adults suggests that adding pyridoxine to folic acid might not provide any additional benefit over folic acid alone (9400,9405,9409,50145). Hyperhomocysteinemia is considered by some to be an independent risk factor for atherosclerosis, recurrent thromboembolism, deep vein thrombosis, myocardial infarction, and ischemic stroke (1899,3323,9402,9405,9408,9409). However, elevated homocysteine levels may be a marker, as opposed to a cause, of vascular disease (11387,11388). A 5 µmol/L increase in plasma homocysteine increases the risk of cerebrovascular disease by 50% and the odds of coronary heart disease by 60% and 80% in males and females, respectively (9407,9411). However, it is not clear if reducing homocysteine levels results in reduced cardiovascular morbidity and mortality (1489,6883,6884,9308,9400,9405,9409). Folic acid, vitamin B6, and vitamin B12 supplementation can reduce total homocysteine from 13.4 to 11 µmol/L. However, this reduction does not seem to help with secondary prevention of death or myocardial infarction, and some research even suggests an increase in cardiovascular disease (CVD) risk (11387,13482,50423,83050,97619). There is also debate about whether supplementation with homocysteine-lowering B vitamins can reduce the risk of stroke. A number of large clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with CVD or impaired renal function (11387,13482,50423,83050,96150). However, a more recent meta-analysis shows that B vitamin supplementation modestly reduces the relative risk of stroke by 10% when compared with placebo in patients at risk for or with a history of CVD (97619). Also, a meta-analysis in patients with a history of stroke shows that B vitamin supplementation modestly reduces the relative risk of stroke recurrence by 13% and the risk of vascular death by 11% when compared with placebo (107136).

Antipsychotic-induced hyperprolactinemia. It is unclear if oral vitamin B6 is beneficial for patients with antipsychotic-induced hyperprolactinemia. Details: Clinical research in male patients with hyperprolactinemia who are on a consistent antipsychotic dose shows that taking vitamin B6 300 mg twice daily for 16 weeks reduces serum prolactin levels by 68%, compared with 37% in patients taking aripiprazole 5 mg twice daily. Also, 67% of patients taking vitamin B6 had prolactin levels less than 40 mcg/mL versus 2% of those taking aripiprazole (107128).
Kidney stones (nephrolithiasis). Oral vitamin B6 seems to decrease urinary oxalate levels and decrease the risk of kidney stone formation in some patients. Details: There is some evidence that taking vitamin B6 (pyridoxine) orally, alone or in combination with magnesium, can decrease urinary oxalate levels in people with type I primary hyperoxaluria, a hereditary disorder (1201,6437,6438,6439,6440,8548,8549,8550). Additionally, a small clinical study in this population suggests that intravenous pyridoxine hydrochloride can reduce urinary oxalate by 25.5% when compared to baseline (90796). In patients with idiopathic hyperoxaluria, taking a combination of pyridoxine 25mg and magnesium oxide 400 mg for 3 months decreases urinary oxalate by approximately 16%, with 68% of patients experiencing a reduction. However, supplementation is less effective than following a low-oxalate diet, which reduces urinary oxalate in 91% of patients by an average of 31% (107127). There is also preliminary evidence that higher pyridoxine intake in females with no history of kidney stones is associated with decreased risk of kidney stone formation (6441), but this association has not been found in males (6442).
Pregnancy-induced nausea and vomiting. Oral vitamin B6 may reduce nausea and vomiting in some pregnant patients and is sometimes used in combination with doxylamine. Details: While some conflicting evidence exists, most small clinical studies suggest that oral vitamin B6 is effective for improving nausea and vomiting associated with pregnancy when compared with baseline or placebo. However, vitamin B6 may not be as effective as ginger (110459). Two small clinical studies show that taking vitamin B6 (pyridoxine) 25 mg every 8 hours for 3-4 days decreases pregnancy-induced nausea severity and vomiting incidence when compared with placebo (6168,16306). A larger clinical trial shows that taking lower doses of vitamin B6, 10 mg every 8 hours over 5 days, improves pregnancy-induced nausea, but not vomiting, when compared with placebo (6167). A small clinical study in patients with mild to moderate nausea and vomiting shows that taking a higher dose of 40 mg twice daily for 4 days is more effective than placebo, but no better than ginger 500 mg twice daily (99404). The American College of Obstetrics and Gynecology (ACOG) considers vitamin B6 at a dose of 10-25 mg 3 to 4 times daily a first-line treatment for pregnancy-induced nausea and vomiting due to its benign safety profile (111601). However, it is not effective for all patients, such as those with hyperemesis gravidarum, a severe form of pregnancy-induced nausea and vomiting. Adding vitamin B6 20 mg three times daily for 2 weeks to intravenous rehydration, metoclopramide, and thiamine seems to be no more effective than placebo for reducing vomiting in hyperemesis gravidarum (99405). Vitamin B6 is also sometimes used in combination with doxylamine. In fact, a combination of vitamin B6 plus doxylamine (Diclegis or Bonjesta, Duchesnay Inc., and various generics) has been approved by the US Food and Drug Administration (FDA) as a prescription product111601). ACOG recommends vitamin B6 in combination with doxylamine as another first-line treatment option (111601). However, the clinical trial used to obtain FDA approval has some methodological problems, and the significance of the results has been questioned. The improvement in symptom scores seen with Diclegis was less than one point on a 13-point scale, which is unlikely to be clinically significant (97998). Also, some clinical research shows that taking pyridoxine 25 mg and doxylamine 12.5 mg is less effective than ondansetron 4 mg when taken every 8 hours for 5 days. Only 41% of the patients using pyridoxine and doxylamine had a clinically significant reduction in nausea, compared to 92% of patients using ondansetron (90797). The combination of vitamin B6 and doxylamine is also studied with acupuncture. A large clinical study in patients with moderate to severe pregnancy-induced nausea and vomiting conducted in China shows that taking vitamin B6-doxylamine (Diclegis, Duchesnay, Inc) 20 to 40 mg each at bedtime for 14 days in combination with daily acupuncture modestly improves patient-reported nausea and vomiting scores when compared with either intervention alone (111820). However, it is unclear whether this improvement is clinically significant.
Premenstrual syndrome (PMS). Oral vitamin B6 seems to reduce PMS symptoms. Details: There is some evidence that taking vitamin B6 (pyridoxine) orally can improve symptoms of PMS such as breast pain or tenderness (mastalgia) and depression in some patients. Pyridoxine in doses of at least 50 mg daily, plus magnesium oxide 200 mg daily, seems to relieve PMS-related anxiety and other symptoms (8555,39007,82962). Although some clinicians advocate doses of pyridoxine 200-500 mg daily for PMS, doses of 50-100 mg daily seem to work just as well. There is no apparent dose-response curve for PMS, so the lowest effective dose should be used. Higher doses might increase the risk of side effects (3093).

POSSIBLY INEFFECTIVE

Age-related cognitive decline. Oral vitamin B6 does not seem to slow age-related cognitive decline. Details: One clinical trial in elderly people with memory complaints shows that taking a combination of B vitamins, including folic acid 0.8 mg, vitamin B12 0.5 mg, and vitamin B6 (form not specified) 20 mg daily for 24 months reduces cerebral atrophy in the gray matter regions associated with Alzheimer disease by up to seven-fold when compared with placebo. However, this protection does not occur in patients with the lowest average blood levels of homocysteine (90374). Furthermore, other clinical research shows that taking vitamin B6 (pyridoxine) 3-75 mg daily in combination with folic acid and vitamin B12 does not improve cognitive function in elderly adults (14392,50225,50510).
Alzheimer disease. Oral vitamin B6 does not seem to improve cognitive function in patients with Alzheimer disease when used in combination with other B vitamins. Also, oral vitamin B6 does not seem to reduce the risk of developing this condition. Details: Clinical research in patients with probable Alzheimer disease taking routine medications shows that taking vitamin B6 25 mg with folic acid 5 mg and vitamin B12 1 mg daily for 18 months does not have a beneficial effect on cognitive function or the severity of disease when compared with placebo. In this study, all patients were consuming a folate-fortified diet (50319). Also, population research in elderly adults has found that a high intake of vitamin B6 from dietary or supplemental sources is not associated with a decreased risk of Alzheimer disease when compared to lower vitamin B6 intake (13165,15270).
Carpal tunnel syndrome. Oral vitamin B6 does not seem to reduce symptoms of carpal tunnel syndrome. Details: Most research shows that people with carpal tunnel syndrome are not generally deficient in vitamin B6 and do not benefit from taking vitamin B6 supplements (8203,8937,9448,9450,9478,9482). Although early studies by a single group of researchers, as well as anecdotal reports, suggest that taking vitamin B6 may relieve carpal tunnel symptoms, more reliable research has not supported these findings (8202,9445,9447,9449,9483,15955,83086).
Cataracts. Oral vitamin B6 does not seem to slow cataract development. Details: Clinical research in females with existing cardiovascular disease (CVD) or at increased risk of CVD shows that taking a combination of folic acid 2.5 mg, vitamin B6 (form not specified) 50 mg, and vitamin B12 1 mg daily for an average of 7.3 years does not reduce the risk of cataracts when compared with placebo. Furthermore, the risk of cataract extraction was increased by 28% (96149).
Chemotherapy-induced acral erythema. While some conflicting evidence exists, most research suggests that oral or topical vitamin B6 does not seem to prevent or reduce the severity of acral erythema induced by chemotherapy. Details: A meta-analysis of 10 clinical trials and 4 observational studies shows that taking vitamin B6 60-500 mg daily for up to 8 chemotherapy cycles does not prevent chemotherapy-induced acral erythema or reduce the incidence of severe cases when compared with control. Most studies used capecitabine chemotherapy alone or in combination, and one study used pegylated liposomal doxorubicin; however, no subgroup analysis was conducted to differentiate chemotherapy regimens. Results did not seem to vary based on study location, study design, or vitamin B6 dose (104930). However, a more recent preliminary clinical study in patients receiving doxorubicin for multiple myeloma shows that taking vitamin B6 100 mg on the first day of chemotherapy then twice daily for 7 days with each cycle reduces the risk of developing acral erythema by 72%, but does not improve the severity of acral erythema, when compared with no vitamin B6 supplementation (110458). Also, one small, low-quality clinical study suggests that taking vitamin B6 400 mg daily reduces the risk of moderate or severe chemotherapy-induced acral erythema when compared with vitamin B6 200 mg daily; however, the higher dose also seems to be associated with worsened tumor response and increased treatment failure (97620). Topical vitamin B6 has also failed to show benefit. A small clinical study in patients with acral erythema from capecitabine or pegylated liposomal doxorubicin shows that applying vitamin B6 1% cream to affected areas three times daily for 6 weeks does not improve symptoms when compared with placebo (104929).
Colorectal adenoma. Oral vitamin B6 does not seem to reduce the risk of developing colorectal adenomas. Details: Clinical research shows that taking a combination of B vitamins, including folic acid 2.5 mg, vitamin B6 (pyridoxine) 50 mg, and vitamin B12 1 mg, daily for up to 9.2 years does not reduce the risk of colorectal adenoma in females at high risk of cardiovascular disease when compared with placebo (90389).
Eclampsia. Oral or intramuscular vitamin B6 does not seem to reduce the risk of eclampsia. Details: Meta-analyses of limited clinical research in pregnant patients show that taking vitamin B6 (pyridoxine), either as 25 mg daily or a single dose of 100 mg orally or intramuscularly, does not reduce the risk of eclampsia when compared with control (83046,96166).
Osteoporosis. Oral vitamin B6 does not seem to reduce the risk of osteoporotic fractures. Details: Clinical research in patients with cerebrovascular disease shows that taking a combination of B vitamins, including folic acid 2 mg, vitamin B6 (form not specified) 25 mg, and vitamin B12 500 mcg daily for up to 10.5 years does not prevent osteoporotic fractures when compared with placebo (90377). Furthermore, a secondary analysis of two large studies in patients with cardiovascular disease has found that taking vitamin B6 (pyridoxine) 40 mg daily in addition to folic acid and vitamin B12 for 1-3 years is associated with a 42% increased risk of hip fracture over an 11-year period when compared with only folic acid and vitamin B12 (96163). This finding is limited because these studies were not designed to assess the effects of vitamin B6 on fracture risk and the analyses were not adjusted for baseline bone health or fall risk.
Pre-eclampsia. Oral or intramuscular vitamin B6 does not seem to reduce the risk of pre-eclampsia. Details: Meta-analyses of limited clinical research in pregnant patients show that taking vitamin B6 (pyridoxine), either as 25 mg daily or a single dose of 100 mg orally or intramuscularly, does not reduce the risk of pre-eclampsia when compared with placebo (83046,96166).
Preterm labor. Oral or intramuscular vitamin B6 does not seem to reduce the risk of preterm labor. Details: Meta-analyses of limited clinical research in pregnant patients shows that taking vitamin B6 (pyridoxine), either as 25 mg daily or a single dose of 100 mg orally or intramuscularly, does not reduce the risk of preterm labor when compared with placebo (83046,96166).

Acne. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults and children with inflammatory acne shows that taking 1-4 tablets of a specific product (NicAzel, Elorac Inc.) containing vitamin B6 (pyridoxine), nicotinamide, azelaic acid, zinc, copper, and folic acid for 8 weeks reduces inflammatory lesions and improves appearance in 88% and 81% of patients, respectively, when compared to baseline (90800). The validity of these findings is limited by the lack of a comparator group.
Age-related macular degeneration (AMD). Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large-scale clinical study shows that taking vitamin B6 (pyridoxine) 50 mg, vitamin B12 1000 mcg, and folic acid 2.5 mg daily reduces the risk for AMD in females over 40 years of age with a history of cardiovascular disease (CVD) or with risk factors for CVD. Those who took this combination for an average of 7.3 years had a 34% reduced risk of developing AMD and a 41% reduced risk of visually significant AMD when compared with placebo (14620). It is unclear if this effect is due to vitamin B6, other ingredients, or the combination.
Angioplasty. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some evidence suggests that vitamin B6 (pyridoxine) 10 mg, folic acid 1 mg, and vitamin B12 400 mcg daily can decrease the rate of restenosis in patients treated with balloon angioplasty (8009,9412). However, this combination does not seem to be as effective for reducing restenosis in patients after coronary stenting (8009). An intravenous loading dose of folic acid, vitamin B6 (pyridoxine), and vitamin B12 followed by oral administration of folic acid 1.2 mcg, vitamin B6 (pyridoxine) 48 mg, and vitamin B12 60 mcg daily after bare metal coronary stenting also does not seem to reduce restenosis and might actually increase restenosis (12150,12151). Due to the lack of evidence of benefit and potential for harm, this combination of vitamins should not be recommended for patients receiving coronary stents (12151). It is unclear if any effects are due to vitamin B6, other ingredients, or the combination.
Antipsychotic-induced metabolic side effects. It is unclear if oral vitamin B6, as an adjunct to progesterone, is beneficial in patients with antipsychotic-induced amenorrhea. Details: A small clinical study in females with antipsychotic-induced amenorrhea shows that taking vitamin B6 80 mg three times daily for 1 month plus intramuscular progesterone daily for 5 days increases levels of estradiol and follicle stimulating hormone, reduces prolactin levels, and increases the rate of clinical efficacy, defined as the normalization of menstruation and improvement in endocrine indicators, by 14% when compared with progesterone alone (110457).
Anxiety. It is unclear if oral vitamin B6 is beneficial in patients with anxiety. Details: Clinical research in college students shows that taking vitamin B6 100 mg daily for one month does not reduce anxiety scores when compared with placebo (110453). However, because a diagnosis of anxiety was not a requirement for study participation, it is unclear if these findings can be generalized to patients diagnosed with anxiety.
Asthma. It is unclear if oral vitamin B6 is beneficial in patients with asthma. Details: Preliminary clinical studies show that taking vitamin B6 (pyridoxine) 200-300 mg daily may improve symptoms of asthma in some patients, but not others, when compared with placebo (7064,7065). Studies have yielded conflicting results, with some research suggesting that it may only be beneficial in children with severe asthma (7065). Additionally, some research suggests that theophylline may lower vitamin B6 levels, although it is unclear if vitamin B6 supplementation is beneficial (4522,7066,9503).
Atherosclerosis. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in patients with intermediate risk for coronary heart disease shows that taking a specific supplement (Kyolic, Total Heart Health, Formula 108, Wakunga) containing vitamin B6 12.5 mg, aged garlic extract 250 mg, vitamin B12 100 mcg, folic acid 300 mcg, and L-arginine 100 mg daily for 12 months reduces coronary artery calcium progression when compared with placebo (88385). It is unclear if this effect is due to vitamin B6, other ingredients, or the combination.
Atopic dermatitis (eczema). It is unclear if oral vitamin B6 is beneficial in patients with eczema. Details: A small clinical study in children with eczema shows that taking vitamin B6 (pyridoxine hydrochloride) 50 mg daily for 4 weeks does not reduce symptoms such as redness and itchiness when compared with placebo (83090).
Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral vitamin B6 is beneficial for ADHD. Details: A small crossover study in children with ADHD shows that taking vitamin B6 600 mg, niacinamide and ascorbic acid 3 grams, and calcium pantothenate 1.2 grams daily for 6 weeks does not improve behavior scores when compared with placebo (9957).
Autism spectrum disorder. Although there is interest in using oral vitamin B6 for autism, there is insufficient reliable information about the clinical effects of vitamin B6 for this condition.
Bipolar disorder. It is unclear if oral vitamin B6 is beneficial in patients with bipolar disorder. Details: A small clinical trial in patients with type 1 bipolar disorder who are taking lithium and experiencing an acute episode of mania shows that taking vitamin B6 80 mg daily for 8 weeks does not improve cognitive function or the severity of mania when compared with placebo. Cognitive function was reduced in patients taking vitamin B6; any effect on sleep was unclear (107132).
Cancer. It is unclear if oral vitamin B6 reduces overall cancer risk. Details: Population research has found that higher dietary intake of vitamin B6 is associated with a 22% reduced risk of cancer, including esophageal, pancreatic, gastric, colorectal, and breast cancer. However, when dietary and supplemental vitamin B6 intake is considered, the inverse association between vitamin B6 and cancer risk is weaker and limited to fewer tumor sites. Furthermore, a meta-analysis of 9 clinical studies shows that taking vitamin B6 3-100 mg orally daily for 2-7.3 years, in combination with vitamin B12 and folate, does not reduce the risk of cancer in patients with cardiovascular disease or kidney failure (96164).
Cardiovascular disease (CVD). Oral vitamin B6, taken along with other B vitamins, does not seem to improve secondary prevention of death or myocardial infarction in patients with CVD. However, it might slightly lower the risk of stroke. Details: Overall evidence from clinical research and meta-analyses shows that taking vitamin B6 in combination with folic acid and/or vitamin B12 does not seem to help with secondary prevention of death or myocardial infarction in patients with or at risk for CVD (11387,13482,34540,50423,83050,90379,97619). In fact, some research suggests that long-term supplementation with vitamin B6, folic acid, and vitamin B12 for secondary prevention increases the risk of CVD by 20% despite lowering homocysteine levels by 30% (13482). However, some research shows that taking vitamin B6 in combination with other B vitamins modestly reduces the risk of stroke, although results are conflicting (11387,13482,50423,83050,96150,96165,97619,107136). Additionally, it is unclear which specific combination of B vitamins is optimal for reducing stroke risk and which patients are most likely to benefit. In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) approved a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368).
Cognitive function. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in healthy adults aged 40-65 years shows that taking a supplement containing vitamin B6, ginkgo leaf, bacopa, and other B vitamins twice daily for 12 weeks does not improve memory or attention when compared with placebo (111334).
Colorectal cancer. It is unclear if oral vitamin B6 reduces the risk of colorectal cancer. Details: A meta-analysis of observational studies suggests that the highest dietary intake of vitamin B6 is associated with a 20% reduced risk of colorectal cancer when compared with the lowest dietary intake. However, this association was not shown in subgroup analyses of studies conducted in Australia, Europe, or North America (111600). The validity of this analysis is limited by the heterogeneity of the included studies.
Dental caries. There is limited evidence on the oral use of vitamin B6 for dental decay during pregnancy. Details: Meta-analyses of limited clinical research show that taking vitamin B6 (pyridoxine), 25 mg daily or a single dose of 100 mg orally or intramuscularly, may reduce the risk of dental decay during pregnancy when compared with placebo (83046,96166).
Depression. It is unclear if oral vitamin B6 reduces the risk of developing depression or improves symptoms of depression. Details: Clinical research in healthy college students shows that taking vitamin B6 100 mg daily for one month does not reduce depression scores when compared with placebo (1104453). However, because a diagnosis of depression was not a requirement for study participation, it is unclear if these findings can be generalized to patients diagnosed with depression. Whether vitamin B6 reduces the risk of developing depression is also unclear. A meta-analysis of population research has found that the highest dietary intake of vitamin B6 is associated with a 19% lower risk of depression when compared with the lowest intake. However, sub-analyses suggest that this association is only relevant in females and not males (107133). In one individual population study in community dwelling older adults included in the analysis, the consumption of at least 1.71 mg of vitamin B6 daily from food was associated with a 43% reduction in the likelihood of becoming depressed when compared with the consumption of 1.33 mg or less daily in females. However, there was no association between vitamin B6 levels and risk of depression in males, and the finding in females was no longer significant when adjusted for total energy intake, since foods rich in vitamin B6 are energy-dense (96168). Another observational longitudinal study in healthy adults starting oral contraceptives containing ethinyl estradiol and levonorgestrel has found that taking vitamin B6 25 mg daily for 6-12 months is associated with a 40% lower risk of depression when compared with no supplementation (90789). Most available studies are cross-sectional in nature, making any conclusions related to causation difficult.
Diabetes. It is unclear if oral vitamin B6 is beneficial in patients with type 2 diabetes or gestational diabetes. Details: Observational research in Chinese adults with type 2 diabetes has found that dietary intake of vitamin B6 in the highest quartile is associated with 53% lower odds of developing cardiovascular disease, defined as a non-fatal myocardial infarction, non-fatal stroke, or hospitalization for unstable angina, when compared with vitamin B6 intake in the lowest quartile (110452). Small clinical studies in patients with gestational diabetes and vitamin B6 deficiency shows that taking vitamin B6 (pyridoxine) 100 mg daily for 2 weeks improves glucose tolerance and blood glucose levels when compared with baseline (82967,83088). However, there is concern that these findings were confounded by dietary alterations. This benefit was not observed in a subsequent small case series in patients with gestational diabetes (22380).
Diabetic neuropathy. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research suggests that taking a combination of B vitamins, including folic acid (L-methylfolate), vitamin B12 (methylcobalamin), and vitamin B6 (pyridoxal-5'-phosphate) for 24 weeks does not improve neural dysfunction based on vibration perception when compared with placebo in patients with diabetic neuropathy. However, taking this combination appears to modestly improve neuropathy symptoms and quality of life related to mental functioning when compared with placebo (90375).
Dysmenorrhea. It is unclear if oral vitamin B6 is beneficial in patients with dysmenorrhea. Details: Preliminary clinical research shows that taking vitamin B6 (form not specified) 200 mg daily reduces pain associated with dysmenorrhea when compared with placebo. However, taking vitamin B6 in combination with magnesium does not reduce pain when compared with placebo (77388).
Fibromyalgia. It is unclear if oral vitamin B6 is beneficial in patients with fibromyalgia. Details: A small clinical study in patients with fibromyalgia shows that taking vitamin B6 80 mg daily for 8 weeks does not improve pain, disease severity, anxiety, depression, or quality of life when compared with placebo (110454).
Gastroenteritis-associated nausea and vomiting. It is unclear if oral vitamin B6 is beneficial in children with gastroenteritis. Details: A small clinical study in children aged 6 months to 12 years with acute viral gastroenteritis shows that taking vitamin B6 (form not specified) does not improve symptoms of dehydration or the frequency of vomiting when compared with placebo (90793).
Hypertension. It is unclear if oral vitamin B6 reduces blood pressure. Details: One small clinical study in patients with essential hypertension shows that taking vitamin B6 (pyridoxine hydrochloride) 5 mg/kg daily for 4 weeks can reduce systolic and diastolic blood pressure when compared with baseline (83091). The validity of this finding is limited by the lack of a control group.
Hypertriglyceridemia. It is unclear if oral vitamin B6 reduces triglyceride levels. Details: Preliminary clinical research shows that vitamin B6 (form not specified) 50 mg daily for 12 weeks does not reduce triglyceride levels in people with hypertriglyceridemia when compared with placebo. However, vitamin B6 appears to decrease total cholesterol and high-density lipoprotein (HDL) cholesterol by approximately 9% in these patients (59028).
Infertility. Although there is interest in using oral vitamin B6 for infertility, there is insufficient reliable information about the clinical effects of vitamin B6 for this condition.
Insomnia. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in healthy adults with self-reported sleep difficulty shows that taking a specific product (LZ Complex3, Sanofi Consumer Healthcare Pty Ltd.) containing vitamin B6, zizyphus extract, hops extract, hydrolyzed milk protein (Lactium), and magnesium oxide nightly, 30 minutes before bed, for 2 weeks does not improve sleep quality, daytime functioning, or physical fatigue when compared with placebo. However, due to the large improvement seen in both the treatment and placebo groups, the effectiveness of this product is unclear (95971).
Isoniazid-induced neuropathy. It is unclear if oral vitamin B6 prevents the development of neuropathy in patients taking isoniazid. Details: Preliminary clinical research in patients taking isoniazid for tuberculosis shows that taking vitamin B6 (pyridoxine) 6 mg daily reduces the development of neuropathy when compared with control (83068).
Lactation. It is unclear if oral vitamin B6 helps to suppress postpartum lactation. Details: A meta-analysis of two small clinical trials shows that taking vitamin B6 (pyridoxine) 400-600 mg daily for 6-7 days postpartum does not suppress lactation when compared with no treatment (83047).
Levetiracetam-induced side effects. While some conflicting evidence exists, several small, low-quality studies suggest that oral vitamin B6 (pyridoxine) may reduce some neuropsychiatric adverse effects related to the use of levetiracetam. Details: In an analysis of case reports, retrospective studies, and a single low-quality prospective study, improvement in levetiracetam-associated neuropsychiatric symptoms occurred in approximately 73% of patients taking pyridoxine (107137). A more recent preliminary clinical trial in children ages 1-17 years shows that taking pyridoxine 10 or 15 mg/kg daily as needed based on symptoms improves behavioral side effects associated with levetiracetam by a small amount when compared with low-dose pyridoxine 0.5 mg/kg daily used as placebo (107124). Also, observational research in children ages 9 months to 14 years has found that taking vitamin B6 is associated with improved behavior and a 44% lower risk of levetiracetam discontinuation when compared with no vitamin B6 supplementation (110455). Some observational research in adults with levetiracetam-associated irritability has found that taking vitamin B6 is associated with an improvement in irritability in 45% of patients when compared to baseline (107129). However, a small clinical trial in adults with epilepsy shows that taking pyridoxine 40 mg daily for 3 weeks does not improve levetiracetam-related psychiatric adverse effects when compared with placebo (110456). This study may have been underpowered to detect differences between groups. Pyridoxine doses used in the studies above have ranged from 50-400 mg daily in children and 40-600 mg daily in adults (107124,107129,107137,110456).
Lung cancer. It is unclear if dietary or oral vitamin B6 reduces lung cancer risk. Details: Epidemiological research has found that higher serum levels of vitamin B6 in male smokers is associated with a lower risk of lung cancer (9454). Also, people with blood levels of vitamin B6 in the top quartile have a modestly lower risk of lung cancer when compared with those whose levels are in the lowest quartile. The association is stronger for males and for people who have smoked (97999). However, other epidemiological research found that increased dietary intake of vitamin B6 is not associated with a reduced risk of lung cancer (96164).
Menopausal symptoms. Although there is interest in using oral vitamin B6 for menopausal symptoms, there is insufficient reliable information about the clinical effects of vitamin B6 for this condition.
Motion sickness. Although there is interest in using oral vitamin B6 for motion sickness, there is insufficient reliable information about the clinical effects of vitamin B6 for this condition.
Nausea and vomiting. It is unclear if oral vitamin B6 is beneficial for nausea and vomiting in patients using oral contraceptives. Details: An observational longitudinal study in healthy females taking oral contraceptives containing ethinyl estradiol and levonorgestrel has found that taking vitamin B6 25 mg daily for 6-12 months is associated with a 43% reduced risk of nausea when compared with no supplementation (90789).
Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral vitamin B6 for patients with NAFLD. Details: A small clinical trial in patients with NAFLD shows that taking vitamin B6 (pyridoxine) 30 mg three times daily for 12 weeks does not reduce levels of liver transaminases or plasma lipids when compared with baseline. However, hepatic fat accumulation was modestly reduced (107130). The validity of this study is limited by the lack of a comparator group.
Obesity. It is unclear if oral vitamin B6 in beneficial in overweight or obese individuals. Details: A small clinical trial in females with a body mass index (BMI) of at least 25 kg/m² shows that taking vitamin B6 as pyridoxine 80 mg daily for 8 weeks reduces fat mass and improves insulin resistance and triglyceride levels by a small amount when compared with placebo. Although some other anthropometric and metabolic indices were improved when compared with baseline, there was no effect of pyridoxine on body weight, visceral adiposity, or other endpoints when compared with placebo (107131).
Overall mortality. It is unclear if oral vitamin B6 reduces the risk of overall mortality. Details: Observational research in US adults has found that dietary intake of vitamin B6 in the highest quintile is associated with a 12% to 21% lower risk of all-cause mortality and a 31% to 44% lower risk of cardiovascular mortality when compared with the lowest quintile of dietary vitamin B6 intake (110451).
Pancreatic cancer. It is unclear if oral vitamin B6 reduces the risk of pancreatic cancer. Details: Observational research has found that higher dietary intake of vitamin B6 is associated with a 37% lower risk of developing pancreatic cancer when compared with lower intake (104927).
Postpartum depression. It is unclear if oral vitamin B6 is beneficial in patients with postpartum depression. Details: Preliminary clinical research in individuals considered at increased risk for postpartum depression, but without clinical depression, shows that taking vitamin B6 80 mg daily from the 28th week of pregnancy until birth, and then 40 mg daily for one month, reduces symptoms of depression 1.5 months after birth when compared with baseline (measured during the third trimester) and when compared with placebo. However, it is unclear if any of the patients included in the study developed postpartum depression, as there were no changes in overall symptoms in patients taking placebo (107126).
Restless legs syndrome (RLS). It is unclear if oral vitamin B6 is beneficial in patients with RLS. Details: A small clinical study in adults with RLS who are beginning treatment with pramipexole shows that also taking vitamin B6 40 mg daily for 2 months moderately improves RLS scores and sleep quality scores when compared with pramipexole and placebo (110052).
Schizophrenia. It is unclear if oral vitamin B6 is beneficial for patients with treatment-resistant schizophrenia. Details: Clinical research in male patients with treatment-resistant schizophrenia who are on a consistent antipsychotic dose shows that adding vitamin B6 300 mg twice daily for 16 weeks modestly improves psychotic symptoms and some measures of cognitive performance when compared with adding aripiprazole 5 mg twice daily (107128). More research is needed to determine if these benefits are clinically relevant.
Seizures. It is unclear if oral vitamin B6 is beneficial for preventing seizures in patients with glycosylphosphatidylinositol (GPI) deficiency. Details: Observational case series in a small number of children and young adults with GPI deficiency has found that taking vitamin B6 20-30 mg/kg daily for 3-12 months is associated with some reduction in seizure frequency in 9 of 13 patients. However, no patient reached seizure freedom (107125,107135). In one case series, treatment for 12 months was associated with modest developmental improvements in almost all patients (107135). The study patient populations were slightly different in terms of age and underlying genetic causes for GPI deficiency.
Sickle cell disease. Oral vitamin B6 has only been evaluated in combination with other B vitamins; its effect when used alone is unclear. Details: Preliminary clinical research in adults with sickle cell disease shows that taking vitamin B6 4.2-6 mg, vitamin B12 4.2-6 mcg, and folic acid 700 mcg daily might lower homocysteine levels. However, it is unknown if this will reduce the risk of endothelial damage in these patients (9324).
Stroke. It is unclear if oral vitamin B6, either alone or with other B vitamins, is beneficial for stroke prevention. Details: There is some debate about whether supplementation with homocysteine-lowering B vitamins, including vitamin B6, can reduce the risk of stroke. A number of clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with cardiovascular disease (CVD) or impaired kidney function (11387,13482,50423,83050,96150). However, a more recent meta-analysis of 10 clinical trials, including over 44,000 patients at risk for or with a history of CVD, shows that B vitamin supplementation reduces the relative risk of stroke by 10% when compared with placebo (97619). This meta-analysis differed from some of the earlier analyses due to the inclusion of several additional clinical trials. Also, another meta-analysis of three clinical trials including 9900 patients with a history of stroke shows that B vitamin supplementation reduces the relative risk of stroke recurrence by 13% when compared with placebo, although this finding was determined to have a low level of certainty. Based on two clinical trials, there was also a 17% reduced risk of vascular death and an 11% reduction in the combined risk of stroke, myocardial infarction, and vascular death (107136). In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) allowed a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368). Unfortunately, even after the publication of higher quality research, it is still unclear which specific combination of B vitamins is optimal and which patients are most likely to benefit. One network meta-analysis shows that a combination of folic acid and vitamin B6 lowers the risk of stroke more effectively than B vitamin mixtures that include vitamin B12 (96165). However, this analysis is limited because it didn't account for dosing. Exposure to low, but not high amounts, of vitamin B12 (cyanocobalamin) seems to reduce stroke risk (96150).
Tardive dyskinesia. It is unclear if oral vitamin B6 prevents tardive dyskinesia in patients taking neuroleptic drugs. Details: A small clinical study in patients taking neuroleptic drugs for schizophrenia shows that taking vitamin B6 (form not specified) 400 mg daily seems to improve Parkinsonian, dystonic, and dyskinetic symptoms when compared with placebo (8558).
Tourette syndrome. Oral vitamin B6 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small, nonblinded clinical study in children aged 4-17 years with untreated Tourette syndrome or with chronic tic disorder and associated symptoms of anxiety shows that taking a liquid nutritional supplement providing vitamin B6 2.8 mg and L-theanine 200 mg daily for 2 months improves scores on the Yale Global Tic Severity Scale, but does not reduce anxiety, when compared with patients receiving psychoeducation (108555). This study may have been inadequately powered to detect a difference between groups.
Vincristine-induced neuropathy. Oral vitamin B6 has only been evaluated in combination with pyridostigmine; its effect when used alone is unclear. Details: A small clinical study in children ages 11 months to 13 years with neuropathy due to vincristine treatment for acute lymphoblastic leukemia, shows that taking vitamin B6 150 mg/m2 and pyridostigmine 3 mg/kg twice daily for 3 months is associated with reduced severity of sensory and motor neuropathy when compared with baseline (104928). The validity of this finding is limited by the lack of a control group. More evidence is needed to rate vitamin B6 for these uses.

Safety view details

Below is general information about the safety of the known ingredients contained in the product StressEez [Discontinued]. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

BACOPA

POSSIBLY SAFE ...when used orally and appropriately, short-term. Bacopa has been used safely in clinical trials at a dose of up to 600 mg daily for up to 12 weeks (10058,10059,17946,97605).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. Clinical research suggests bacopa extract might be safe to use at a dose of 225 mg daily for up to 6 months or 320 mg daily for up to 14 weeks in children aged 6-14 years (33304,97603,109625).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

GOTU KOLA

POSSIBLY SAFE ...when used topically and appropriately. Gotu kola has been used safely in a cream or ointment for up to 10 weeks (11072,11073,67372,102792,105329,105335). An emulsion containing gotu kola extract 3% and other ingredients has been applied safely to the skin twice daily for up to 60 days (111571). ...when used orally and appropriately. Gotu kola extract has been used with apparent safety in doses of up to 180 mg daily for up to 12 months or 1000 mg daily for 60 days. Dried gotu kola has been used with apparent safety in doses of up to 2200 mg daily for 4 weeks (6887,11062,11063,11064,11065,11066,11067,11068,11069,11070)(11071,99756,99757,99758,105329,105332,105333). A specific gotu kola extract (Centellicum, Horphag Research Ltd) 450-675 mg daily has been used with apparent safety for up to 6 weeks (99756,99757).

PREGNANCY: POSSIBLY SAFE
when used topically and appropriately (11073,13559). There is insufficient reliable information available about the safety gotu kola when used orally during pregnancy; avoid using.

LACTATION:
Insufficient reliable information available; avoid using.

LIKELY SAFE ...when used orally and appropriately. A tolerable upper intake level (UL) has not been established for thiamine, and doses up to 50 mg daily have been used without adverse effects (15,6243). ...when used intravenously or intramuscularly and appropriately. Injectable thiamine is an FDA-approved prescription product (15,105445).

CHILDREN: LIKELY SAFE
when used orally and appropriately in dietary amounts. A tolerable upper intake level (UL) has not been established for healthy individuals (6243).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in dietary amounts of 1. 4 mg daily. A tolerable upper intake level (UL) has not been established for healthy individuals (3094,6243).

VALERIAN

LIKELY SAFE ...when used orally and appropriately, short-term. Valerian 300-600 mg daily has been safely used in clinical studies in over 12,000 patients for up to 6 weeks (2074,3484,3485,4032,15018,17577,17578,19409,96242,103221)(104010,105718). There is insufficient reliable information available about the safety of valerian when used orally for longer than 6 weeks.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. Valerian 160-320 mg has been used with apparent safety in children under 12 years of age for 4-8 weeks (14416).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

VITAMIN B6

LIKELY SAFE ...when used orally and appropriately in doses that do not exceed the tolerable upper intake level (UL) of 100 mg daily for adults (15). ...when used parenterally and appropriately. Injectable vitamin B6 (pyridoxine) is an FDA-approved prescription product (15).

POSSIBLY SAFE ...when used orally and appropriately in doses of 101-200 mg daily (6243,8558).

POSSIBLY UNSAFE ...when used orally in doses at or above 500 mg daily. High doses, especially those exceeding 1000 mg daily or total doses of 1000 grams or more, pose the most risk. However, neuropathy can occur with lower daily or total doses (6243,8195). ...when used intramuscularly in high doses and frequency due to potential for rhabdomyolysis (90795).

CHILDREN: LIKELY SAFE
when used orally and appropriately (3094).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately in amounts exceeding the recommended dietary allowance (5049,8579,107124,107125,107135).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses, long-term (3094).

PREGNANCY: LIKELY SAFE
when used orally and appropriately. A special sustained-release product providing vitamin B6 (pyridoxine) 75 mg daily is FDA-approved for use in pregnancy. Vitamin B6 (pyridoxine) is also considered a first-line treatment for nausea and vomiting in pregnancy by the American College of Obstetrics and Gynecology (111601). However, it should not be used long-term or without medical supervision and close monitoring.

PREGNANCY: POSSIBLY UNSAFE
when used orally in excessive doses. There is some concern that high-dose maternal vitamin B6 (pyridoxine) can cause neonatal seizures (4609,6397,8197).

LACTATION: LIKELY SAFE
when used orally in doses not exceeding the recommended dietary allowance (RDA) (3094). The RDA in lactating women is 2 mg daily. There is insufficient reliable information available about the safety of vitamin B6 when used in higher doses in breast-feeding women.

Interactions with Drugs view details

Below is general information about the interactions of the known ingredients contained in the product StressEez [Discontinued]. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

BACOPA

ANTICHOLINERGIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concurrent use might decrease the effectiveness of both agents.

Details

Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels, which could counteract the effects of anticholinergic drugs (17946). Similarly, anticholinergic drugs might counteract the cholinergic effects of bacopa.

CEVIMELINE (Evoxac)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might increase the effects and adverse effects of cevimeline.

Details

In one case, a 58-year-old female taking cevimeline long-term for Sjogren syndrome experienced hyperhidrosis, malaise, nausea, and tachycardia shortly after taking a single dose of bacopa. Symptoms resolved after two days. Cevimeline is metabolized by cytochrome P450 (CYP) 2D6 and CYP3A4, and researchers theorize that bacopa may have inhibited these isoenzymes (109627). However, it is unclear if bacopa causes clinically significant inhibition of either CYP2D6 or CYP3A4.

CHOLINERGIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, concurrent use of bacopa with other cholinergic drugs might have additive effects.

Details

Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels (17946). Theoretically, this could result in additive cholinergic effects when used with cholinergic drugs.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might increase the levels and adverse effects of CYP1A2 substrates.

Details

Research on the effects of bacopa extracts on CYP1A2 enzymes is conflicting. Some in vitro evidence shows that bacopa extract can moderately and non-competitively inhibit CYP1A2, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might increase the levels and adverse effects of CYP2C19 substrates.

Details

In vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C19 enzymes (97606). It is not known whether this is clinically significant.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might increase the levels and adverse effects of CYP2C9 substrates.

Details

Research on the effect of bacopa extracts on CYP2C9 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C9, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might increase the levels and adverse effects of CYP3A4 substrates.

Details

Research on the effects of bacopa extracts on CYP3A4 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and competitively inhibit CYP3A4, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

THYROID HORMONE

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, bacopa might have additive effects when used with thyroid hormone.

Details

Animal research suggests that bacopa increases thyroxine (T4) levels in mice by about 40% (33286).

GOTU KOLA

CNS DEPRESSANTS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking gotu kola might increase the sedative effects of CNS depressants.

Details

In vitro research suggests that gotu kola may have sedative effects via binding of GABA receptors (6887,11071).

HEPATOTOXIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking gotu kola with hepatotoxic drugs might have additive adverse effects.

Details

There are at least four case reports of hepatotoxicity associated with the use of gotu kola. However, more information is needed to determine if gotu kola was the causative factor in these cases (13182,92506).

TRIMETHOPRIM (Proloprim)

Interaction Rating = Minor Be watchful with this combination.

Severity = Insignificant • Occurrence = Probable • Level of Evidence = B

Trimethoprim might increase blood levels of thiamine.

Details

In vitro, animal, and clinical research suggest that trimethoprim inhibits intestinal thiamine transporter ThTR-2, hepatic transporter OCT1, and renal transporters OCT2, MATE1, and MATE2, resulting in paradoxically increased thiamine plasma concentrations (111678).

VALERIAN

ALCOHOL (Ethanol)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Valerian can have additive sedative effects when used concomitantly with alcohol.

Details

Valerian has sedative effects (9894). Theoretically, valerian might have an additive sedative effect when combined with alcohol. Excessive sedation has been reported in an alcohol-abusing individual who took valerian and Gingko biloba (19426). However, the potential interaction between valerian and alcohol has been disputed in other research. Limited evidence suggests that a combination of valerian 160 mg and lemon balm 80 mg (Euvegal) does not cause further deterioration in reaction ability and reaction rate when taken with alcohol as compared to the effects of alcohol alone (19427).

ALPRAZOLAM (Xanax)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Valerian can have additive sedative effects when used with alprazolam. Also, valerian in high doses might modestly increase alprazolam levels, though this is not likely to be clinically significant.

Details

Valerian has sedative effects (9894). Theoretically, valerian might cause additive sedation when combined with alprazolam. Also, a small pharmacokinetic study shows that taking valerian extract 1000 mg daily (providing 11 mg valerenic acid) might increase alprazolam levels by about 19%. This might be due to valerian's mild inhibition of cytochrome P450 3A4 (CYP3A4) (13014). Despite being statistically significant, this increase is not likely to be clinically significant.

CNS DEPRESSANTS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Valerian can have additive sedative effects when used concomitantly with CNS depressant drugs.

Details

Theoretically, concomitant use of valerian and drugs with sedative and anesthetic properties may cause additive therapeutic and adverse effects (3486,12720,19429).

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Unlikely • Level of Evidence = B

Valerian does not seem to have a clinically relevant effect on levels of drugs metabolized by CYP2D6.

Details

Although some in vitro evidence suggests that valerian affects CYP2D6, clinical pharmacokinetic (PK) studies show that valerian is unlikely to affect the CYP2D6 enzyme (13014,13536,19430,19431). In one PK study, taking valerian 1000 mg (providing about 11 mg valerenic acid) nightly for 14 days did not affect the metabolism of dextromethorphan, a CYP2D6 substrate. In another PK study, taking valerian 125 mg three times daily for 28 days did not affect metabolism of debrisoquine, an accepted CYP2D6 probe-substrate (13014,13536).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = B

Valerian does not seem to have a clinically relevant effect on levels of drugs metabolized by CYP3A4.

Details

Although some in vitro evidence suggests that valerian extract might inhibit or induce CYP3A4, clinical pharmacokinetic (PK) studies show that valerian does not have a clinically significant effect on the CYP3A4 enzyme (6450,12214,13014,13536,19431). In one PK study, taking valerian 125 mg three times daily for 28 days did not affect metabolism of midazolam, an accepted CYP3A4 probe-substrate. In another PK study, taking valerian 1000 mg (providing about 11 mg valerenic acid) nightly for 14 days modestly increases levels of alprazolam, a CYP3A4 substrate, suggesting mild inhibition of CYP3A4 (13014,13536). However, this mild inhibition is unlikely to be clinically relevant.

GLUCURONIDATED DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Valerian might weakly inhibit glucuronidation and increase concentrations of drugs metabolized by UGT1A1 and UGT2B7.

Details

In vitro research shows that methanolic valerian extract and valerenic acid might competitively inhibit UDP-glucuronosyltransferase (UGT) 1A1 (UGT1A1) and UGT2B7 (81685).

VITAMIN B6

AMIODARONE (Cordarone)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.

Details

Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect (8892,8893).

ANTIHYPERTENSIVE DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.

Details

Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure (30859,82959,83093). Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine (83091).

LEVODOPA

Interaction Rating = Minor Be watchful with this combination.

Severity = Moderate • Occurrence = Unlikely • Level of Evidence = D

Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.

Details

Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people (3046).

PHENOBARBITAL (Luminal)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.

Details

Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6 (3046,10801).

PHENYTOIN (Dilantin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.

Details

Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6 (3046,10801).

Report an Adverse Reaction to StressEez [Discontinued]

Adverse Effects view details

Below is general information about the adverse effects of the known ingredients contained in the product StressEez [Discontinued]. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

BACOPA

General ...Orally, bacopa is generally well tolerated.
Most Common Adverse Effects:
Orally: Abdominal cramps, diarrhea, dry mouth, headache, nausea.

Cardiovascular ...Orally, bacopa has been reported to cause palpitations (10058).

Gastrointestinal ...Orally, bacopa has been reported to cause abdominal cramps, abdominal pain, bloating, decreased appetite, diarrhea, dry mouth, excessive thirst, flatulence, indigestion, nausea, and increased stool frequency. Rates of adverse gastrointestinal events have ranged from 12% to 30% (10058,17946,33295,97605,109623,111520).

Musculoskeletal ...Orally, bacopa has been reported to cause arthralgia, muscle fatigue, and myopathy (10058,109623,111522). In one case, a 21-year-old male experienced progressive proximal weakness, muscle atrophy, weight loss, dark urine, and elevated serum markers of myopathy, with muscle biopsy showing immune-mediated necrotizing myopathy, after taking a supplement containing bacopa for 5 years (111522).

Neurologic/CNS ...Orally, bacopa has been reported to cause drowsiness, headache, insomnia, and vivid dreams (10058,10059,17946,109623).

Other ...Orally, bacopa has been reported to cause flu like symptoms and fatigue (10058,97605,111520).

GOTU KOLA

General ...Orally and topically, gotu kola seems to be well tolerated.
Most Common Adverse Effects:
Orally: Gastric irritation and nausea.
Topically: Eczema.
Serious Adverse Effects (Rare):
Orally: Hepatotoxicity.

Dermatologic ...Topically, gotu kola may cause eczema (10277,10278). Also, gotu kola can cause allergic contact dermatitis, characterized by erythema, itching, papules, and a burning sensation (4,6887,9789,52875,52887,52896,52902). One specific gotu kola product (Blasteostimulina,Almirall, S. A.) has been reported to cause allergic contact dermatitis. However, not all patients with reactions to this product are sensitive to gotu kola; some patients are sensitive to neomycin, another ingredient in the product (52875). Madecassol ointment (Rona Laboratories Limited) is another gotu kola product that has resulted in allergic contact dermatitis. Controlled testing suggests that this product can cause this adverse effect in about 8% of patients (9789). Centellase cream has also caused allergic contact dermatitis in at least two cases (52887,52888).

Gastrointestinal ...In some patients, gotu kola can extract cause gastrointestinal upset and nausea (780,6887,52894).

Hepatic ...There is concern that gotu kola may cause liver toxicity in some patients. There are at least four case reports of hepatotoxicity associated with gotu kola; however, hepatotoxic contaminants cannot be ruled out, as laboratory analysis was not conducted on the products used. Additionally, the doses of gotu kola used in these cases were not reported (13182,92506). In a clinical trial where liver function was monitored, taking gotu kola 120 mg daily for 6 months was not associated with changes in liver function (11065).
In one case of hepatotoxicity, a 61-year-old female developed elevated liver transaminase and total bilirubin levels after taking gotu kola tablets for 30 days. Liver biopsy showed granulomatous acute hepatitis. Months later, the patient took gotu kola again and developed elevated liver transaminases after 2 weeks. In another case, a 52-year-old female developed symptoms of hepatitis and increased liver transaminases after taking gotu kola for 3 weeks. Biopsy indicated chronic hepatitis and granulomas, areas of necrosis, and cirrhotic transformation. Liver function normalized after discontinuation of gotu kola. In a third case, a 49-year-old female developed symptoms of hepatitis after taking gotu kola for 2 months. Biopsy revealed granulomatous hepatitis. Liver function normalized after discontinuation of gotu kola (13182). In a fourth case, a 15-year-old female taking an unknown dose of gotu kola and lymecycline for 6 weeks for acne experienced acute liver failure with abdominal pain and vomiting, as well as elevated liver transaminases, bilirubin, international normalized ratio (INR), and prothrombin. Liver function returned to normal after both products were discontinued (92506).

Immunologic ...Topically, gotu kola can cause allergic contact dermatitis, characterized by erythema, itching, papules, and a burning sensation (4,6887,9789,52875,52887,52896,52902). One specific gotu kola product (Blasteostimulina, Almirall, S. A.) has been reported to cause allergic contact dermatitis in some patients. However, not all patients who react to this product are sensitive to gotu kola; some are sensitive to neomycin, another ingredient in the product (52875). Madecassol ointment (Rona Laboratories Limited) is another gotu kola product that has resulted in allergic contact dermatitis. Controlled testing suggests that this product can cause this adverse effect in about 8% of patients (9789). Centellase cream has also caused allergic contact dermatitis in at least two cases (52887,52888).

Psychiatric ...A case of night eating syndrome has been reported for a 41-year-old female who had been taking a gotu kola tincture (dose not specified) for 2 years. Symptoms resolved after gotu kola use was discontinued (52878).

General ...Orally and parenterally, thiamine is generally well tolerated.
Serious Adverse Effects (Rare):
Parenterally: Hypersensitivity reactions including angioedema and anaphylaxis.

Immunologic ...Orally, thiamine might rarely cause dermatitis and other allergic reactions. Parenterally, thiamine can cause anaphylactoid and hypersensitivity reactions, but this is also rare (<0.1%). Reported symptoms and events include feelings of warmth, tingling, pruritus, urticaria, tightness of the throat, cyanosis, respiratory distress, gastrointestinal bleeding, pulmonary edema, angioedema, hypotension, and death (15,35585,105445).
In one case report, a 46-year-old female presented with systemic allergic dermatitis after applying a specific product (Inzitan, containing lidocaine, dexamethasone, cyanocobalamin and thiamine) topically by iontophoresis; the allergic reaction was attributed to thiamine (91170).

VALERIAN

General ...Orally, valerian is generally well-tolerated.
Most Common Adverse Effects:
Orally: Dizziness, drowsiness, and mental slowness. Other reported side effects include headache, gastrointestinal upset, excitability, and vivid dreams. When used chronically and abruptly stopped, symptoms of withdrawal such as tachycardia, anxiety, irritability, and insomnia might occur. Advise patients to taper doses slowly after extended use.
Serious Adverse Effects (Rare):
Orally: Several case reports raise concerns about hepatotoxicity after the use of valerian and valerian-containing multi-ingredient dietary supplements. Withdrawal from chronic valerian use has been associated with cases of cardiac failure and hallucinations.

Cardiovascular ...When used orally in high doses for an extended period of time, valerian withdrawal has been associated with tachycardia and high output cardiac failure in one patient with a history of coronary artery disease (3487). Chest tightness has been reported for an 18-year-old female who took 40-50 capsules containing valerian 470 mg/capsule (659). A case of severe hypotension, suspected to be due to vasodilation, hypocalcemia, and hypokalemia, has been reported for a patient who injected an unknown quantity of a crude tap water extract of raw valerian root (81734).

Dermatologic ...Orally, valerian might rarely cause a rash. A case of valerian-related rash that resolved after valerian root discontinuation was reported in clinical research (19422).

Gastrointestinal ...Orally, valerian has been associated with increased incidence of gastrointestinal problems including diarrhea, nausea, vomiting, and stomach pain (15046,19406,19407,19422,110712). In one individual, taking 20 times the normal dose caused abdominal cramping (659).

Hepatic ...There have been several case reports of hepatotoxicity associated with the use of multi-ingredient oral preparations containing valerian (8243,96241). In one case report, a 57-year-old man presented with acute hepatitis after consuming a cold and flu remedy containing valerian 2 grams for 3 days; the remedy also contained white willow, elderberry, and horseradish. Although the use of the cold and flu remedy was discontinued one month prior to symptom presentation, the acute hepatitis was attributed to valerian root and treated with steroids (96241). It is possible, however, that some of these preparations may have been adulterated with hepatotoxic agents (8243).
Hepatotoxicity involving long-term use of single-ingredient valerian preparations has also been reported (3484,17578). Also, a case of a 38-year-old female with liver insufficiency and cirrhosis of a vascular parenchymal nature who developed hepatotoxic symptoms following valerian and ethyl-alcohol abuse has been reported (81697). Symptoms resolved and laboratory values normalized following intense plasmapheresis treatment. Another case of acute hepatitis characterized by elevated aminotransferases, mild fibrosis, and liver inflammation has been reported for a 50-year-old female who consumed valerian root extract 5 mL three times weekly along with 10 tablets of viamine, a product containing dry valerian extract 125 mg/tablet, for 2 months (81696). Because a variety of doses were used in these cases, and many people have used higher doses safely, these hepatotoxic reactions might have been idiosyncratic. Tell patients the long-term effect of valerian on liver function is unknown.

Musculoskeletal ...In a case report, combined intake of valerian and passionflower caused throbbing and muscular fatigue when taken concomitantly with lorazepam (19429).

Neurologic/CNS ...Orally, valerian might cause dizziness, headaches, fatigue, sleepiness, and mental dullness (3484,17578,19411,19422,81723,89407). The severity of adverse effects appears to increase with higher doses (19411). However, taking valerian extracts in doses up to 1800 mg does not appear to significantly affect mood or psychomotor performance (10424,15044). Valerian does not usually have a negative impact on reaction time, alertness, and concentration the morning after intake (2074,8296). Clinical research shows that a single dose of valerian root 1600 mg is not associated with any changes in sleepiness, reaction time, or driving performance within 1-4 hours after intake (96240). More serious side effects may occur when valerian is taken at higher doses. In one individual, 20 times the normal dose caused tremor of the hand and foot and lightheadedness (659). In a case report, combined intake of valerian and passionflower caused shaking of the hands and dizziness when taken concomitantly with lorazepam (19429).

Psychiatric ...Orally, valerian has been associate with reports of restlessness, excitability, uneasiness, agitation, and vivid dreams (3484,17578,19411,19422). Chronic use and rapid cessation can lead to withdrawal syndrome with symptoms of agitation, insomnia, and hallucinations (104003). There appears to be a trend towards increased severity of adverse effects with higher doses (19411). A case of acute hypomania has been reported for a 21-year-old female patient who took a valerian decoction in water each night for one month to treat subclinical anxiety. Symptoms included euphoric mood, rapid speech, and increased sociability and sexual interest. Following cessation of valerian use and treatment with quetiapine 100 mg daily for two weeks, the patient recovered (89405). In another case report, an 85-year-old male with mild cognitive impairment, major depression, anxiety, and chronic kidney disease presented to the emergency department with hallucinations, confusion, and agitation thought to be due to abrupt cessation after taking valerian 600 mg daily for about 6 months. The symptoms resolved in about 5 days (104003).

VITAMIN B6

General ...Orally or by injection, vitamin B6 is well tolerated in doses less than 100 mg daily.
Most Common Adverse Effects:
Orally or by injection: Abdominal pain, allergic reactions, headache, heartburn, loss of appetite, nausea, somnolence, vomiting.
Serious Adverse Effects (Rare):
Orally or by injection: Sensory neuropathy (high doses).

Dermatologic ...Orally, vitamin B6 (pyridoxine) has been linked to reports of skin and other allergic reactions and photosensitivity (8195,9479,90375). High-dose vitamin B6 (80 mg daily as pyridoxine) and vitamin B12 (20 mcg daily) have been associated with cases of rosacea fulminans characterized by intense erythema with nodules, papules, and pustules. Symptoms may persist for up to 4 months after the supplement is stopped, and may require treatment with systemic corticosteroids and topical therapy (10998).

Gastrointestinal ...Orally or by injection, vitamin B6 (pyridoxine) can cause nausea, vomiting, heartburn, abdominal pain, mild diarrhea, and loss of appetite (8195,9479,16306,83064,83103,107124,107127,107135). In a clinical trial, one patient experienced infectious gastroenteritis that was deemed possibly related to taking vitamin B6 (pyridoxine) orally up to 20 mg/kg daily (90796). One small case-control study has raised concern that long-term dietary vitamin B6 intake in amounts ranging from 3.56-6.59 mg daily can increase the risk of ulcerative colitis (3350).

Hematologic ...Orally or by injection, vitamin B6 (pyridoxine) can cause decreased serum folic acid concentrations (8195,9479). One case of persistent bleeding of unknown origin has been reported in a clinical trial for a patient who used vitamin B6 (pyridoxine) 100 mg twice daily on days 16 to 35 of the menstrual cycle (83103). It is unclear if this effect was due to vitamin B6 intake.

Musculoskeletal ...Orally or by injection, vitamin B6 (pyridoxine) can cause breast soreness or enlargement (8195).

Neurologic/CNS ...Orally or by injection, vitamin B6 (pyridoxine) can cause headache, paresthesia, and somnolence (8195,9479,16306). Vitamin B6 (pyridoxine) can also cause sensory neuropathy, which is related to daily dose and duration of intake. Doses exceeding 1000 mg daily or total doses of 1000 grams or more pose the most risk, although neuropathy can occur with lower daily or total doses as well (8195). The mechanism of the neurotoxicity is unknown, but is thought to occur when the liver's capacity to phosphorylate pyridoxine via the active coenzyme pyridoxal phosphate is exceeded (8204). Some researchers recommend taking vitamin B6 as pyridoxal phosphate to avoid pyridoxine neuropathy, but its safety is unknown (8204). Vitamin B6 (pyridoxine) neuropathy is characterized by numbness and impairment of the sense of position and vibration of the distal limbs, and a gradual progressive sensory ataxia (8196,10439). The syndrome is usually reversible with discontinuation of pyridoxine at the first appearance of neurologic symptoms. Residual symptoms have been reported in patients taking more than 2 grams daily for extended periods (8195,8196). Tell patients daily doses of 100 mg or less are unlikely to cause problems (3094).

Oncologic ...In females, population research has found that a median intake of vitamin B6 1. 63 mg daily is associated with a 3.6-fold increased risk of rectal cancer when compared with a median intake of 1.05 mg daily (83024). A post-hoc subgroup analysis of results from clinical research in adults with a history of recent stroke or ischemic attack suggests that taking folic acid, vitamin B12, and vitamin B6 does not increase cancer risk overall, although it was associated with an increased risk of cancer in patients who also had diabetes (90378). Also, in patients with nasopharyngeal carcinoma, population research has found that consuming at least 8.6 mg daily of supplemental vitamin B6 during treatment was associated with a lower overall survival rate over 5 years, as well as a reduced progression-free survival, when compared with non-users and those with intakes of up to 8.6 mg daily (107134).

Report an Adverse Reaction to StressEez [Discontinued]