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Research · Supplements

Vitamin B6

Pooled trials found less nausea in pregnancy on vitamin B6, though a Cochrane review called the evidence limited. Low-quality PMS trials found symptoms improved. B vitamin combinations lowered homocysteine without changing heart attacks. High intakes cause sensory nerve damage. EFSA based its 12 mg limit on it, and Australia will restrict products above 50 mg a day from June 2027.

Add to Bio HackChecked 2026-11-09
Status
Dietary supplement in the US. Doxylamine with pyridoxine is a prescription drug in the US for nausea and vomiting of pregnancy.
Also called
pyridoxine, pyridoxine hydrochloride, pyridoxal, pyridoxal 5'-phosphate, P5P, PLP, pyridoxamine
Taken for
nausea in pregnancy, morning sickness, PMS, breast pain, mood, depression, energy, heart health, homocysteine, nerve health, carpal tunnel, memory

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help4

Reported risks5

What people take it for, and what was found

Shown to help4

ModerateStudied in pregnancy

Nausea and vomiting in pregnancy

Shown to ease nausea in pregnancy slightly, under 1 point on nausea scales. Vomiting did not differ significantly in one trial.

The numbers and sources
Effect
Pooled, pyridoxine alone or with another agent improved nausea scores by 0.78 points on the Rhodes scale (95% CI 0.26 to 1.31) and 0.75 points on the PUQE scale (95% CI 0.28 to 1.22) [1]. In a Thai trial, nausea scores fell more on 30 mg a day than on placebo over 5 days (P = 0.0008). Vomiting episodes did not significantly differ (P = 0.055) [2].
Population
18 studies [1]; 342 women at 17 weeks' gestation or earlier [2].
Sources
[1], [2], [3]
Caveats
Sources disagree on strength. A 2015 Cochrane review of 41 trials found only limited evidence for vitamin B6 and could not pool most outcomes [3]. The 2023 pooled scores mix pyridoxine alone with combinations [1].
ModerateStudied in women

Premenstrual syndrome

Shown to improve overall premenstrual symptoms and premenstrual depression over placebo in women with PMS, in mostly low-quality trials from a 1999 review.

The numbers and sources
Effect
Across 9 trials, women on vitamin B6 were more likely than on placebo to report better overall premenstrual symptoms (OR 2.32, 95% CI 1.95 to 2.54) and better premenstrual depression (OR 1.69, 95% CI 1.39 to 2.06, 4 trials) [4].
Population
940 women with premenstrual syndrome in 9 published trials [4].
Sources
[4]
Caveats
The authors rated most trials low quality. Doses ran up to 100 mg a day [4]. The review is from 1999.
Limited

Depression symptoms

One trial found lower depression scores over 1 month only in adults with mild or worse symptoms at baseline. Anxiety and stress did not change.

The numbers and sources
Effect
Over 1 month, 100 mg of pyridoxine a day lowered depression scores more than placebo or 1,000 µg of B12 only in participants with mild or worse depression symptoms at baseline (partial η² 0.20). Anxiety and stress scores did not change [5].
Population
267 adults from the general population, 215 of them female. 58 had mild or worse depression symptoms at baseline [5].
Sources
[5]
Caveats
One trial, and the effect appeared in a subgroup defined by baseline scores. Participants were not patients with diagnosed depression [5].
LimitedStudied in women

Memory in postmenopausal women

One trial without placebo found memory scores rose from baseline over 6 months in postmenopausal women with mild cognitive impairment in India.

The numbers and sources
Effect
Over 6 months, scores on the Montreal Cognitive Assessment rose from baseline on 25 mg of pyridoxine a day (p = 0.0323), and homocysteine fell. The abstract reports change from baseline, not a comparison with the untreated group [7].
Population
180 postmenopausal women with mild cognitive impairment in India, randomized to pyridoxine, 100 mg of vitamin C, or no treatment [7].
Sources
[7]
Caveats
One trial with no placebo. Menopause quality of life scores did not change overall [7].

Mixed results1

Moderate

Heart attack, stroke and death

Mixed results: stroke was about 10% lower in pooled trials of B6, mostly with folic acid and B12, while heart attack and death did not change.

The numbers and sources
Effect
Across 15 trials of vitamins B6, B9 or B12, heart attack (RR 1.02, 95% CI 0.95 to 1.10) and death from any cause (RR 1.01, 95% CI 0.96 to 1.06) did not change. Stroke was lower (RR 0.90, 95% CI 0.82 to 0.99) [8]. In HOPE-2, 50 mg of B6 with folic acid and B12 lowered homocysteine by 2.4 µmol/L. Major cardiovascular events did not change (RR 0.95, 95% CI 0.84 to 1.07) and stroke fell (RR 0.75, 95% CI 0.59 to 0.97) [9]. In NORVIT, 40 mg of B6 alone did not change recurrent events (RR 1.14, 95% CI 0.98 to 1.32) [10].
Population
71,422 participants in 15 trials [8]; 5,522 people aged 55 or older with vascular disease or diabetes, 5 years [9]; 3,749 people within 7 days of a heart attack, median 40 months [10].
Sources
[8], [9], [10]
Caveats
Most trials combined B6 with folic acid and B12, so B6 alone cannot be separated. The Cochrane authors rated the heart attack and mortality evidence high quality [8].

Not shown to help1

LimitedStudied in women

Cyclic breast pain

Limited evidence: breast pain did not differ from placebo across 3 low-quality trials.

The numbers and sources
Effect
Across 3 trials, breast pain intensity did not differ between vitamin B6 and placebo (SMD -3.57, 95% CI -9.15 to 2.01) [6].
Population
Otherwise healthy women with breast pain, 3 placebo-controlled trials [6].
Sources
[6]
Caveats
The authors rated the certainty very low and the trials low quality. Heterogeneity was extreme (I² 99.56%) [6].

Doses studied

The Thai pregnancy trial used 30 mg of pyridoxine a day [2]. PMS trials used up to 100 mg a day [4]. HOPE-2 used 50 mg a day with 2.5 mg folic acid and 1 mg B12 [9], and NORVIT 40 mg a day [10]. The depression trial used 100 mg a day for 1 month [5], and the memory trial 25 mg a day for 6 months [7]. EFSA took 50 mg a day as its reference point for nerve damage and set a tolerable upper intake level of 12 mg a day for adults, including during pregnancy and lactation [11].

Risks

Reported risks5

LimitedHow often is not known

Sensory nerve damage (peripheral neuropathy)

Case reports: high-dose B6 was followed by sensory nerve damage, sometimes disabling, improving after stopping. EFSA calls the link well established.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Seven adults developed ataxia and severe sensory loss after daily high-dose pyridoxine. Four were severely disabled, and all improved after stopping [12]. A 2023 systematic review of 20 articles found high B6 levels linked to a mainly sensory, axonal neuropathy that people report improving after stopping [13]. EFSA calls the link between excess B6 and peripheral neuropathy well established and bases its upper limit on it. It drew its 50 mg a day reference point from a case-control study, supported by case reports and vigilance data [11].
Population
Case series of 7 adults [12]; 20 articles [13]; EFSA systematic reviews [11].
Sources
[11], [12], [13]
Caveats
Evidence is case reports, case-control and vigilance data, not trials. EFSA could not set a lowest dose that causes harm from human data. It notes an inverse relationship between dose and time to symptoms [11].
ModerateHow often is not known

Regulator actions in Australia and the Netherlands

Australia's TGA states neuropathy risk cannot be excluded below 50 mg a day and requires a warning above 10 mg. The Netherlands capped supplements at 21 mg.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Australia's TGA has required a peripheral neuropathy warning on medicines with more than 10 mg of vitamin B6 a day since March 2022. From 1 June 2027, oral products with more than 50 mg and up to 200 mg per daily dose become Pharmacist Only Medicines, and those above 200 mg still need a prescription. The TGA states that the risk of neuropathy cannot be excluded below 50 mg a day. As of 31 October 2025, its adverse event database held 250 reports of peripheral neuropathy and related conditions for products containing vitamin B6 [14]. In October 2026 it opened a consultation on stronger warning statements and clearer labeling of the presence and amount of B6 [15]. The Netherlands lowered the maximum daily dose in supplements to 21 mg from October 2018. Of 224 Dutch neuropathy reports through 2023, only one after that date mentioned a dose well above 21 mg, and reports per period fell from the second half of 2019 [16].
Population
Products sold in Australia [14][15]; spontaneous reports in the Netherlands [16].
Sources
[14], [15], [16]
Caveats
Spontaneous reports cannot give a rate. Dutch reports describing neuropathy at lower doses continued after 2018, and the authors call for study of low-dose products [16].
LimitedHow often is not known

More cardiovascular events with B6, folic acid and B12 after a heart attack

One trial found heart attack, stroke and sudden death trended higher with B6, folic acid and B12 after a heart attack. Another found more unstable angina.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
In the group given 40 mg B6 with folic acid and B12, the primary composite of heart attack, stroke and sudden coronary death trended higher than placebo (RR 1.22, 95% CI 1.00 to 1.50, P = 0.05) [10]. In HOPE-2, hospitalization for unstable angina was higher on B6, folic acid and B12 (RR 1.24, 95% CI 1.04 to 1.49) [9].
Population
3,749 people after a heart attack in Norway [10]; 5,522 people with vascular disease or diabetes [9].
Sources
[9], [10]
Caveats
Across 15 trials, serious adverse events did not significantly differ (RR 1.07, 95% CI 1.00 to 1.14) [8].
LimitedHow often is not known

Lung cancer in men

Linked to about 82% more lung cancer in men taking over 20 mg a day of B6 from single supplements for 10 years, higher in smokers. No link in women.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Men averaging more than 20 mg a day of B6 from single supplements over 10 years had more lung cancer than nonusers (HR 1.82, 95% CI 1.25 to 2.65). Risk was higher in men who smoked at baseline. Women showed no association, and B6 from multivitamins showed none [17].
Population
77,118 adults aged 50 to 76, 808 lung cancers [17].
Sources
[17]
Caveats
One observational cohort with self-reported supplement use.
LimitedStudied in womenHow often is not known

Hip fracture

Linked to about 29% more hip fractures in postmenopausal women taking 35 mg a day or more of B6, and more with high B12 too.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Women with B6 intakes of 35 mg a day or more had more hip fractures than those under 2 mg (RR 1.29, 95% CI 1.04 to 1.59). With 35 mg or more of B6 and 20 µg or more of B12 combined, the RR was 1.47 (95% CI 1.15 to 1.89) [18].
Population
75,864 postmenopausal US nurses followed 30 years, 2,304 hip fractures [18].
Sources
[18]
Caveats
One observational cohort with intake from food frequency questionnaires. The linear trend for B6 alone was not significant (P = 0.06) [18].

Claims tested and not found

  1. That B6 prevents heart attacks by lowering homocysteine. Homocysteine fell, and heart attacks and deaths did not change [8][9].
  2. That B6 alone protects after a heart attack. In NORVIT, 40 mg a day did not change recurrent cardiovascular events [10].
  3. That B6 eases cyclic breast pain. Three pooled placebo-controlled trials found no difference in pain intensity [6].

Sources

  1. Jayawardena R, Majeed S, Sooriyaarachchi P, et al. The effects of pyridoxine (vitamin B6) supplementation in nausea and vomiting during pregnancy: a systematic review and meta-analysis. Archives of Gynecology and Obstetrics. 2023. https://doi.org/10.1007/s00404-023-06925-w
  2. Vutyavanich T, Wongtra-ngan S, Ruangsri R. Pyridoxine for nausea and vomiting of pregnancy: A randomized, double-blind, placebo-controlled trial. American Journal of Obstetrics and Gynecology. 1995. https://doi.org/10.1016/0002-9378(95)90359-3
  3. Matthews A, Haas DM, O'Mathúna DP, et al. Interventions for nausea and vomiting in early pregnancy. Cochrane Database of Systematic Reviews. 2015. https://doi.org/10.1002/14651858.CD007575.pub4
  4. Wyatt KM, Dimmock PW, Jones PW, et al. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ. 1999. https://doi.org/10.1136/bmj.318.7195.1375
  5. Field DT, Cracknell R, Biagi N. High Dose Vitamin B6 Reduces Depression Symptoms. Depression and Anxiety. 2026. https://doi.org/10.1155/da/8926512
  6. Sharifipour F, Siahkal SF, Bagherinia M. The effectiveness of vitamin B6 in reducing mastalgia: a systematic review and meta-analysis. BMC Women's Health. 2025. https://doi.org/10.1186/s12905-025-03991-x
  7. Dhivya K, Sarumathy S, Manigandan G. A randomized, controlled trial to evaluate the efficacy of pyridoxine and ascorbic acid on cognitive function and quality of life in post-menopausal women. Naunyn-Schmiedeberg's Archives of Pharmacology. 2025. https://doi.org/10.1007/s00210-025-04205-9
  8. Martí-Carvajal AJ, Solà I, Lathyris D, et al. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database of Systematic Reviews. 2017. https://doi.org/10.1002/14651858.CD006612.pub5
  9. Lonn E, Yusuf S, Arnold MJ, et al. Homocysteine Lowering with Folic Acid and B Vitamins in Vascular Disease. New England Journal of Medicine. 2006. https://doi.org/10.1056/NEJMoa060900
  10. Bønaa KH, Njølstad I, Ueland PM, et al. Homocysteine Lowering and Cardiovascular Events after Acute Myocardial Infarction. New England Journal of Medicine. 2006. https://doi.org/10.1056/NEJMoa055227
  11. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Bohn T, et al. Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA Journal. 2023. https://doi.org/10.2903/j.efsa.2023.8006
  12. Schaumburg H, Kaplan J, Windebank A, et al. Sensory Neuropathy from Pyridoxine Abuse. New England Journal of Medicine. 1983. https://doi.org/10.1056/NEJM198308253090801
  13. Muhamad R, Akrivaki A, Papagiannopoulou G, et al. The Role of Vitamin B6 in Peripheral Neuropathy: A Systematic Review. Nutrients. 2023. https://doi.org/10.3390/nu15132823
  14. Therapeutic Goods Administration. Medicines containing vitamin B6 (pyridoxine, pyridoxal or pyridoxamine). Medicine Safety Update. 2026. https://www.tga.gov.au/news/safety-updates/medicines-containing-vitamin-b6-pyridoxine-pyridoxal-or-pyridoxamine
  15. Therapeutic Goods Administration. TGA seeks public views on stronger vitamin B6 labelling for low-risk medicines. Media release. 2026. https://www.tga.gov.au/news/media-releases/tga-seeks-public-views-stronger-vitamin-b6-labelling-low-risk-medicines
  16. van Hunsel F, Scholl J, Vrolijk M, et al. Impact of Regulatory Action on Dose Maximalization for Vitamin B6 Dietary Supplements on the Reporting Pattern for Neuropathy. Pharmacoepidemiology and Drug Safety. 2025. https://doi.org/10.1002/pds.70108
  17. Brasky TM, White E, Chen CL. Long-Term, Supplemental, One-Carbon Metabolism-Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort. Journal of Clinical Oncology. 2017. https://doi.org/10.1200/JCO.2017.72.7735
  18. Meyer HE, Willett WC, Fung TT, et al. Association of High Intakes of Vitamins B6 and B12 From Food and Supplements With Risk of Hip Fracture Among Postmenopausal Women in the Nurses' Health Study. JAMA Network Open. 2019. https://doi.org/10.1001/jamanetworkopen.2019.3591

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