- Vitamin B6 (pyridoxine) is required for the synthesis of the neurotransmitters serotonin and norepinephrine and for myelin formation.
- Pyridoxine deficiency in adults principally affects the peripheral nerves, skin, mucous membranes, and the blood cell system. In children, the central nervous system (CNS) is also affected. Deficiency can occur in people with uremia, alcoholism, cirrhosis, hyperthyroidism, malabsorption syndromes, congestive heart failure (CHF), and in those taking certain medications.
- Mild deficiency of vitamin B6 is common. Major sources of vitamin B6 include: cereal grains, legumes, vegetables (carrots, spinach, peas), potatoes, milk, cheese, eggs, fish, liver, meat, and flour.
- Pyridoxine is frequently used in combination with other B vitamins in vitamin B complex formulations.
- 2-Methyl-3-hydroxy-4,5-dihydroxymethylpyridine, 5-hydroxy-6-methyl-3,4-pyridinedimethanol [65-23-6], Adermine Hydrochloride, B Complex Vitamin, B6, B (6), Bio Zinc, Beesix, Benadon, Bexivit, Bonadon N, Hexobion 100, Naturetime B6, Pyridoxal, Pyridoxal Phosphate, Pyridoxal-5-Phosphate, Pyridoxamine, Pyridoxine HCl, Pyridoxine Hydrochloride, Pyroxin, Rodex, Vicotrat, Vita-Valu, Vitabee 6, Vitamin B-6.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
|Uses based on scientific evidence||Grade*
|Hereditary sideroblastic anemia
Pyridoxine supplements are effective for treating hereditary sideroblastic anemia under the supervision of a qualified healthcare provider.
|Preventing adverse effects in people taking cycloserine (Seromycin®)
Cycloserine is a prescription antibiotic that may cause anemia, peripheral neuritis, or seizures by acting as a pyridoxine antagonist or increasing excretion of pyridoxine. Requirements for pyridoxine may be increased in patients receiving cycloserine. Pyridoxine may be recommended by a healthcare provider to prevent these adverse effects.
|Pyridoxine deficiency/ neuritis
Pyridoxine supplements are effective for preventing and treating pyridoxine deficiency and neuritis due to inadequate dietary intake, certain disease states, or deficiency induced by drugs such as isoniazid (INH) or penicillamine. Dietary supplements should be taken under the guidance of a qualified healthcare provider.
|Pyridoxine-dependent seizures in newborns
Pyridoxine-dependent seizures in newborns can result from the use of high-dose pyridoxine in pregnant mothers or from genetic (autosomal recessive) pyridoxine dependency. Refractory seizures in newborns that are caused by pyridoxine dependence may be controlled quickly with intravenous administration of pyridoxine by a qualified healthcare provider.
|Akathisia (movement disorder)
Some prescription drugs called neuroleptics, which are used in psychiatric conditions, may cause movement disorders as an unwanted side effect. Vitamin B6 has been studied for the treatment of acute neuroleptic-induced akathisia (NIA) in schizophrenic and schizoaffective disorder patients. Preliminary results indicate that high doses of vitamin B6 may be useful additions to the available treatments for NIA, perhaps due to its combined effects on various neurotransmitter systems. Further research is needed to confirm these results.
There are conflicting findings about the potential benefit or harm of taking folic acid plus vitamin B6 and vitamin B12 following angioplasty. Further research is needed before a strong recommendation can be made.
Preliminary research suggests that children with severe asthma might have inadequate pyridoxine status. Theophylline, a prescription drug used to help manage asthma, seems to lower pyridoxine levels. Studies of pyridoxine supplementation in asthma patients taking theophylline yield conflicting results. Further research is needed before a strong conclusion can be drawn.
|Attention deficit hyperactivity disorder (ADHD)
Some research suggests that pyridoxine supplementation alone or in combination with high doses of other B vitamins might help ADHD. Other studies show no benefit. Further research is needed before a conclusion can be drawn.
Studies of birth outcomes with vitamin B6 supplementation during pregnancy yield mixed results. Further well-designed clinical trials might be helpful in this area.
|Cardiovascular disease / hyperhomocysteinemia
High homocysteine levels in the blood (hyperhomocysteinemia) are a risk factor for cardiovascular disease, blood clotting abnormalities, myocardial infarction (heart attack), and ischemic stroke. Taking pyridoxine supplements alone or in combination with folic acid has been shown to be effective for lowering homocysteine levels. However, it is not clear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. Until definitive data is available, the current recommendation is screening of 40 year-old men and 50 year-old women for hyperhomocysteinemia.Decreased pyridoxine concentrations are also associated with increased plasma levels of C-reactive protein (CRP). CRP is an indicator of inflammation that is associated with increased cardiovascular morbidity in epidemiologic studies.Investigation of more renal transplant recipients undergoing longer treatment with Vitamin B6 is needed as study results conflict.
|Carpal tunnel syndrome
Preliminary data suggests that large doses of vitamin B6 may be helpful for carpal tunnel syndrome. Well-designed clinical trials are needed before a firm conclusion can be drawn.
Preliminary evidence suggests that because pyridoxine increases serotonin and GABA levels in the blood, it may benefit people in dysphoric mental states. Well-designed clinical trials are needed to confirm potential benefit.
|Hyperkinetic cerebral dysfunction syndrome
There is preliminary evidence that pyridoxine supplementation might benefit hyperkinetic children who have low levels of blood serotonin. Further research is needed to confirm these results.
|Immune system function
Vitamin B6 is important for immune system function in older individuals. One study found that the amount of vitamin B6 required to reverse immune system impairments in elderly people was more than the current recommended dietary allowance (RDA). Well-designed clinical trials on vitamin B6 supplementation for this indication are needed before a recommendation can be made.
|Kidney stones (nephrolithiasis)
Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which can contribute to a certain type of kidney stones. Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation. Benefit has not been proven in other types of kidney stones such as those associated with high urinary calcium, phosphorus, and creatinine. Further data is needed before a firm conclusion can be drawn.
Study results of pyridoxine used to suppress lactation yield mixed results. Well-designed clinical trials are needed before a firm conclusion can be drawn.
Epidemiological research suggests that male smokers with higher serum levels of pyridoxine may have a lower risk of lung cancer. Well-designed clinical trails of pyridoxine supplementation are needed to confirm these results and supplementation is not standard therapy at this time.
|Pregnancy-induced nausea and vomiting
Studies of the use of pyridoxine alone or in combination with other anti-nausea treatments in pregnant women yield conflicting results. Further research is needed before a strong recommendation can be made.
|Premenstrual syndrome (PMS)
There is some evidence that taking pyridoxine orally may improve symptoms of PMS such as breast pain or tenderness (mastalgia) and PMS-related depression or anxiety in some patients. Further research is needed before a recommendation can be made.
|Preventing vitamin B6 deficiency associated with taking birth control pills
The need for vitamin B6 supplementation in women taking birth control pills has not been proven although some studies show decreased pyridoxine levels in these women. Supplementation of B6 should be approached cautiously since the long-term effect of such therapy is uncertain.
Pyridoxine has some antioxidant effects, which theoretically may benefit patients with tardive dyskinesia. Results from a small high-quality trial suggest a benefit of vitamin B6 on symptoms of tardive dyskinesia. Further research is needed before a recommendation can be made.
Studies of B6 supplementation alone or in combination with magnesium have not been shown to benefit autism. Autism should be treated by a qualified healthcare provider.
Pyridoxine alone or in combination with B12 and folic acid orally does not seem to be useful for preventing stroke recurrence.
Uses based on tradition or theory
*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Acne, alcohol intoxication, allergies, appetite stimulation, arthritis, cancer prevention, chorea, conjunctivitis (pinkeye), cystitis, diabetic neuropathy, diuresis (increased urine production), dizziness, Down's syndrome, high cholesterol, improving dream recall, infertility, menopausal symptoms, migraine headaches, motion sickness, muscle cramps, night leg cramps, poisoning (mushroom), psychosis, radiation sickness, sickle cell anemia, skin conditions.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (over 18 years old)
- Recommended Dietary Allowances (RDAs) of vitamin B6: Males (19-50 years) 1.3 milligrams; males (51 years and older) 1.7 milligrams; females (19-50 years) 1.3 milligrams; females (51 years and older) 1.5 milligrams. Some researchers think the RDA for women 19-50 years should be increased to 1.5-1.7 milligrams per day. Pregnant women, 1.9 milligrams; and lactating women, 2 milligrams.
- Recommended maximum daily intake of vitamin B6: Adults, pregnant, and lactating women (over 18 years) 100 milligrams. A doctor and pharmacist should be consulted for dosing in other conditions.
Children (under 18 years old)
- Recommended Dietary Allowances (RDAs) of vitamin B6: Infants (0-6 months) 0.1 milligrams; infants (7-12 months) 0.3 milligrams; children (1-3 years) 0.5 milligrams; children (4-8 years) 0.6 milligrams; children (9-13 years) 1 milligram; males (14-18 years) 1 milligram per day; females (14-18 years) 1.2 milligrams per day.
- Recommended maximum daily intake of vitamin B6: Children (1-3 years) 30 milligrams; (4-8 years) 40 milligrams; children (9-13 years) 60 milligrams. Males, females, pregnant, and lactating females (14-18 years) 80 milligrams.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
- Patients should avoid vitamin B6 products if they are sensitive or allergic to any of their ingredients.
Side Effects and Warnings
- Some individuals seem to be particularly sensitive to vitamin B6 and may have problems at lower doses. Overall, pyridoxine is generally considered safe in adults and children when used appropriately at recommended doses. Avoid excessive dosing.
- Acne, skin reactions, allergic reactions, and photosensitivity have been reported.
- Nausea, vomiting, abdominal pain, loss of appetite, and increased liver function test results (serum aspartate transaminase (AST, SGOT)) have been reported.
- Headache, paresthesia, somnolence, and sensory neuropathy have been reported.
- Breast soreness or enlargement, decreased serum folic acid levels, seizures after large doses, hypotonia, and respiratory distress in infants have also been reported.
Pregnancy and Breastfeeding
- Vitamin B6 is likely safe when used orally in doses not exceeding the recommended dietary allowance (RDA). Vitamin B6 is possibly safe when used orally and appropriately in amounts exceeding the recommended dietary allowance. A special sustained-release multi-ingredient product is U.S. Food and Drug Administration (FDA)-approved for use in pregnancy. However, it should not be used long-term or without medical supervision and close monitoring or in more excessive doses. There is some concern that high-dose maternal pyridoxine can cause neonatal seizures.
- Vitamin B6 is likely safe when used orally in doses not exceeding the Recommended Dietary Allowance (RDA). There is insufficient reliable information about the safety of pyridoxine when used in higher doses in lactating women. Because most breastfeeding women do not consume the RDA of vitamin B6 in their normal diets and do not provide totally breastfed infants with the RDA of this vitamin, higher doses of vitamin B6 may be recommended although benefits have not been well proven.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
- Preliminary research suggests that pyridoxine could exacerbate amiodarone (Cordarone®)-induced photosensitivity. Other research suggests a protective effect. Due to conflicting information, a firm conclusion cannot be drawn at this time but monitoring may be warranted.
- Destruction of normal gastrointestinal flora by antibiotics can cause decreased production of the B vitamins. Clinical significance is unknown.
- Cycloserine is an antibiotic that may cause anemia or peripheral neuritis by acting as a pyridoxine antagonist or increasing renal excretion of pyridoxine. Requirements for pyridoxine may be increased in patients receiving cycloserine.
- Use of estrogens and estrogen-containing oral contraceptives can interfere with pyridoxine metabolism, reducing serum pyridoxine levels. The need for pyridoxine supplementation has not been adequately studied.
- Hydralazine (Apresoline®) can increase pyridoxine requirements. The need for pyridoxine supplementation has not been adequately studied.
- Isoniazid (INH, Rifamate®) can increase pyridoxine requirements.
- Pyridoxine enhances the metabolism of levodopa (Sinemet®), reducing its anti-parkinsonism effects. Carbidopa and levodopa used together may avoid this interaction.
- Penicillamine (Cuprimine®, Depen®) can increase pyridoxine requirements.
- Preliminary data suggests that pyridoxine can reduce plasma levels of phenobarbital (Luminal®), possibly by increasing metabolism. Patients taking phenobarbital should avoid high doses of pyridoxine.
- Preliminary data suggests that pyridoxine can reduce plasma levels of phenytoin (Dilantin®), possibly by increasing metabolism. Patients taking phenytoin should avoid high doses of pyridoxine.
- Theophylline (Theo-Dur®), a medication used for asthma, interferes with pyridoxine metabolism. Study results of supplemental pyridoxine in these patients are inconclusive.
Interactions with Herbs and Dietary Supplements
- Theoretically, herbs and supplements with estrogen-like activity may interact with pyridoxine. The need for pyridoxine supplementation has not been adequately studied.
- This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Ethan M. Basch, MD (Memorial Sloan-Kettering Cancer Center); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Cynthia Dacey, PharmD (Northeastern University); Jenna Hollenstein (Natural Standard Research Collaboration); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Christine Ulbricht, BS (University of Massachusetts); Mamta Vora, PharmD (Northeastern University); Wendy Weissner, BA (Natural Standard Research Collaboration).
- Chittumma P, Kaewkiattikun K, Wiriyasiriwach B. Comparison of the effectiveness of ginger and vitamin B6 for treatment of nausea and vomiting in early pregnancy: a randomized double-blind controlled trial. J Med Assoc Thai 2007 Jan;90(1):15-20.
- Clarke R, Armitage J. Vitamin supplements and cardiovascular risk: review of the randomized trials of homocysteine-lowering vitamin supplements. Semin Thromb Hemost 2000;26(3):341-348.
- Findling RL, Maxwell K, Scotese-Wojtila L, et al. High-dose pyridoxine and magnesium administration in children with autistic disorder: an absence of salutary effects in a double-blind, placebo-controlled study. J Autism Dev Disord 1997;27(4):467-478.
- Leeda M, Riyazi N, de Vries JI, et al. Effects of folic acid and vitamin B6 supplementation on women with hyperhomocysteinemia and a history of preeclampsia or fetal growth restriction. Am J Obstet Gynecol 1998;179(1):135-139.
- Lerner V, Miodownik C, Kaptsan A, et al. Vitamin B6 treatment for tardive dyskinesia: a randomized, double-blind, placebo-controlled, crossover study. J Clin Psychiatry 2007 Nov;68(11):1648-54.
- Lerner V, Bergman J, Statsenko N, et al. Vitamin B6 treatment in acute neuroleptic-induced akathisia: a randomized, double-blind, placebo-controlled study. J Clin Psychiatry 2004;65(11):1550-1554.
- Miodownik C, Lerner V, Statsenko N, et al. Vitamin B6 versus mianserin and placebo in acute neuroleptic-induced akathisia: a randomized, double-blind, controlled study. Clin Neuropharmacol 2006 Mar-Apr;29(2):68-72.
- Miodownik C, Lerner V, Vishne T, et al. High-dose vitamin B6 decreases homocysteine serum levels in patients with schizophrenia and schizoaffective disorders: a preliminary study. Clin Neuropharmacol 2007 Jan-Feb;30(1):13-7.
- Nye C, Brice A. Combined vitamin B6-magnesium treatment in autism spectrum disorder. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD003497.
- Rimm EB, Willett WC, Hu FB, et al. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA 2-4-1998;279(5):359-364.
- Sahakian V, Rouse D, Sipes S, Rose N, et al. Vitamin B6 is effective therapy for nausea and vomiting of pregnancy: a randomized, double-blind placebo-controlled study. Obstet Gynecol 1991;78(1):33-36.
- Schnyder G, Roffi M, Flammer Y, et al. Effect of homocysteine-lowering therapy with folic acid, vitamin B12, and vitamin B6 on clinical outcome after percutaneous coronary intervention: the Swiss Heart study: a randomized controlled trial. JAMA 8-28-2002;288(8):973-979.
- Thaver D, Saeed MA, Bhutta ZA. Pyridoxine (vitamin B6) supplementation in pregnancy. Cochrane Database Syst Rev 2006 Apr 19;(2):CD000179.
- Woodside JV, Yarnell JW, McMaster D, et al. Effect of B-group vitamins and antioxidant vitamins on hyperhomocysteinemia: a double-blind, randomized, factorial-design, controlled trial. Am J Clin Nutr 1998;67(5):858-866.
- Wyatt KM, Dimmock PW, Jones PW, et al. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ 5-22-1999;318(7195):1375-1381.
March 01, 2008.
This evidence-based monograph was prepared by the Natural Standard Research Collaboration. The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. Talk to your health care provider before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Copyright© 2008 Natural Standard (www.naturalstandard.com). All Rights Reserved.