Disclosure: We earn commissions on purchases made through our links. This never influences our scores. Editorial policy
Vitamin B6
Bottom line
In our scoring, Vitamin B6 rates likely effective: the research is fairly solid for premenstrual symptoms. Our top-scored product is Nature Made Vitamin B6 100 mg (90/100), about $0.10 a day at a clinical dose of PMS up to 100 mg/day. Bottom line: a reasonable pick if it fits your goal. This is our opinion, not medical advice; talk to your clinician before starting.
Here is the part most supplement aisles skip: vitamin B6 is one of the few water-soluble vitamins that is genuinely neurotoxic in excess.
- Evidence
- Likely Effective
- Category
- Vitamins & Minerals
- Best form
- pyridoxine HCl (the form used in the efficacy trials)
- Effective dose
- PMS up to 100 mg/day
- Lab tested
- 6 of 7 products
- Category
- Vitamins & Minerals
- Best form
- pyridoxine HCl (the form used in the efficacy trials)
- Effective dose
- PMS up to 100 mg/day
- Lab tested
- 6 of 7 products
Key takeaways
- →B6 has two evidence-backed uses at safe doses: premenstrual symptom relief (up to 100 mg/day) and nausea in early pregnancy (10-30 mg, clinician-guided).
- →It is neurotoxic in excess - the adult ceiling is 100 mg/day, and chronic high doses cause sensory nerve damage. This is not a 'more is better' vitamin.
- →The efficacy trials used pyridoxine HCl. P5P costs more and is marketed as better absorbed, but that claim is not evidence-backed - both forms share the same neuropathy ceiling.
- →Nature Made (USP Verified pyridoxine HCl, ~$0.10/day) is our top pick; many single-ingredient B6 caps are dosed at exactly 100 mg, so watch for double-dosing with a multivitamin or B-complex.
What Is Vitamin B6?
Here is the part most supplement aisles skip: vitamin B6 is one of the few water-soluble vitamins that is genuinely neurotoxic in excess. It is not a "take extra, flush the rest" nutrient like B12 or vitamin C. Chronic high doses cause sensory nerve damage, which is why there is a firm ceiling on it - 100 mg/day for adults - and why a lot of single-ingredient B6 products, dosed at exactly 100 mg per capsule, put you at that ceiling in one pill. Stack one of those on top of a multivitamin or B-complex and you can quietly walk past the limit. So the honest frame here is not "how much can B6 do for me" but "what is the one or two things it actually helps, at a dose that stays safe."
There are two of those things, and both have real trial support. The first is premenstrual symptoms: a systematic review of nine randomized trials (about 940 women) found B6 at up to 100 mg/day beat placebo, though the authors were careful to note most of those trials were low quality. The second is nausea in early pregnancy, where the evidence is cleaner - pyridoxine at 30 mg/day significantly reduced nausea versus placebo, and ACOG (the main US obstetrics body) names vitamin B6 as a first-line option for nausea and vomiting of pregnancy, alone or paired with doxylamine. If you are pregnant, this is a with-your-clinician decision, not a solo one, and the dose stays low (10-25 mg every 6-8 hours).
Where B6 does not deliver is just as important. It reliably lowers homocysteine (a blood marker), and for years that got sold as heart protection - but the big NORVIT trial, giving a folic acid plus B6 plus B12 combination, lowered the number and produced no cardiovascular benefit, with a trend toward harm. The pattern repeats across trials: B6 moves the marker, not the events. It has also long been pitched for carpal tunnel syndrome, and controlled trials do not back that up - a randomized trial found no difference versus placebo on symptoms or nerve conduction.
On form, ignore the upsell. The efficacy trials used pyridoxine HCl, the plain, cheap form. P5P (pyridoxal 5'-phosphate) is the "active" coenzyme form and gets marketed as better absorbed, but that claim is not evidence-backed - your liver converts pyridoxine to P5P readily on its own, and no trial shows P5P works better for the uses that matter. It also costs more. Both forms share the exact same neuropathy ceiling, so paying up for P5P buys you a pricier route to the same 100 mg limit. Buy the form the trials used, keep the dose at or under 100 mg/day, and count what you are already getting from any B-complex or multivitamin.
Does It Work? The Evidence
How A-F grades workVitamin B6 earns a Likely Effective rating on the strength of its best-supported uses: eases premenstrual symptoms and reduces nausea of early pregnancy (grade B). The table below grades every claimed benefit on its own, including weaker and more heavily marketed uses, so one strong result never stands in for the rest.
Lowers homocysteine but does not cut cardiovascular events
Bonaa et al. 2006 (NORVIT, N Engl J Med): a folic acid + B6 + B12 regimen lowered homocysteine but produced NO cardiovascular benefit (a trend toward harm); the pattern is consistent across trials - B6 lowers the number, not the events
High chronic doses cause sensory neuropathy
Schaumburg et al. 1983 (N Engl J Med): the landmark case series - sensory ataxia and neuropathy from chronic high-dose pyridoxine (~2-6 g/day); later reports document neuropathy at chronic intakes as low as ~100-200 mg/day, which is why the adult UL is 100 mg/day
Eases premenstrual symptoms
Wyatt et al. 1999 (BMJ) systematic review of 9 RCTs (940 women): odds ratio ~2.3 favoring B6 over placebo, doses up to 100 mg/day; authors caveat most trials were low quality
Reduces nausea of early pregnancy
Vutyavanich et al. 1995 (Am J Obstet Gynecol), 342 women: pyridoxine 30 mg/day significantly reduced nausea vs placebo; ACOG names vitamin B6 (10-25 mg every 6-8h), alone or with doxylamine, as first-line for nausea and vomiting of pregnancy
Relieves carpal tunnel syndrome
Spooner et al. 1993 (Can Fam Physician) RCT: no difference vs placebo on symptoms or nerve conduction; controlled trials do not support B6 for carpal tunnel
| Grade | Claimed Benefit | Key Studies | Our Verdict |
|---|---|---|---|
| A | Lowers homocysteine but does not cut cardiovascular events | Bonaa et al. 2006 (NORVIT, N Engl J Med): a folic acid + B6 + B12 regimen lowered homocysteine but produced NO cardiovascular benefit (a trend toward harm); the pattern is consistent across trials - B6 lowers the number, not the events | Ineffective |
| A | High chronic doses cause sensory neuropathy | Schaumburg et al. 1983 (N Engl J Med): the landmark case series - sensory ataxia and neuropathy from chronic high-dose pyridoxine (~2-6 g/day); later reports document neuropathy at chronic intakes as low as ~100-200 mg/day, which is why the adult UL is 100 mg/day | Supported |
| B | Eases premenstrual symptoms | Wyatt et al. 1999 (BMJ) systematic review of 9 RCTs (940 women): odds ratio ~2.3 favoring B6 over placebo, doses up to 100 mg/day; authors caveat most trials were low quality | Supported |
| B | Reduces nausea of early pregnancy | Vutyavanich et al. 1995 (Am J Obstet Gynecol), 342 women: pyridoxine 30 mg/day significantly reduced nausea vs placebo; ACOG names vitamin B6 (10-25 mg every 6-8h), alone or with doxylamine, as first-line for nausea and vomiting of pregnancy | Supported |
| D | Relieves carpal tunnel syndrome | Spooner et al. 1993 (Can Fam Physician) RCT: no difference vs placebo on symptoms or nerve conduction; controlled trials do not support B6 for carpal tunnel | Ineffective |
How to Choose: Forms, Doses & What Matters
Clinical dose: PMS up to 100 mg/day; pregnancy nausea 10-30 mg (clinician-guided); do not exceed 100 mg/day (the UL)
Best forms: pyridoxine HCl (the form used in the efficacy trials), P5P is the active form but not proven superior and costs more, stay at or under 100 mg/day - the tolerable upper limit
For premenstrual symptoms, the trials used up to 100 mg/day of pyridoxine, taken daily; there is no need to go higher, and going higher raises the neuropathy risk without adding benefit. For pregnancy nausea, the studied and ACOG-referenced approach is 10-25 mg every 6-8 hours (so roughly 30-75 mg/day), ideally under your obstetrician's guidance rather than self-dosed. Pyridoxine HCl is the form used in the efficacy studies, so there is no reason to pay more for P5P - your body converts pyridoxine to the active form on its own. Take it with or without food. The single most important habit is to add up your total B6 from all sources: a standalone B6 cap plus a B-complex plus a multivitamin can quietly push you over the 100 mg/day ceiling, so check every label you take.
Who Should Take Vitamin B6?
The clearest case is premenstrual symptoms: if you get cyclical mood and physical symptoms before your period, a systematic review of nine trials supports B6 up to 100 mg/day, and it is cheap enough to try for a few cycles. The second clear case is nausea in early pregnancy - ACOG lists vitamin B6 (10-25 mg every 6-8 hours) as a first-line option, alone or with doxylamine, but this is a conversation to have with your obstetrician rather than a solo decision, both on dose and on pairing. Outside those two, most people who eat a normal diet already get enough B6 from food (poultry, fish, potatoes, chickpeas, bananas), and a standalone supplement is not doing much. A few people with documented deficiency or on certain medications may need it, but that is a call for their doctor, not a shelf-grab.
Who Should Avoid It?
Not for everyone
Side Effects & Safety
Product Scores
7 products scored on dosing accuracy, third-party testing, cost per effective dose, and label transparency.
The Scorecard: 7 Products Compared
Nature Made Vitamin B6 100 mg
Nature Made$10.48 ÷ 105 days at 100mg/day (1 serving × 100mg)
USP Verified pyridoxine HCl at the trial-matched dose. The obvious default: it uses the exact form the efficacy studies used and carries the only independent certification in this group. Just do not stack it on top of a B-complex.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
NOW Foods Vitamin B-6 (Pyridoxine HCl) 100 mg
NOW Foods$12.24 ÷ 245 days at 100mg/day (1 serving × 100mg)
The value-minded way to get the right form from a reputable manufacturer. Not independently certified like Nature Made, but the form and dose are exactly what the trials used.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
Nutricost Vitamin B6 (Pyridoxine HCl) 100 mg
Nutricost$11.95 ÷ 398 days at ~60mg/day (0.6 servings × 100mg)
The cost-per-dose winner with the right form and dose. The brand states it runs ISO-accredited batch testing, but there is no consumer-facing seal, so it trades some verification for price versus USP-verified Nature Made.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
Thorne Pyridoxal 5'-Phosphate (P5P)
Thorne$20.00 ÷ 182 days at 34mg/day (1 serving × 34mg)
A clean, well-made P5P from a highly regarded brand - but P5P itself is not the trial form and is not proven to work better than pyridoxine HCl, so the premium buys quality assurance rather than a better outcome.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
Pure Encapsulations P5P 50
Pure Encapsulations$40.00 ÷ 182 days at 33mg/day (1 serving × 33mg)
The cleanest formulation of the P5P options and a sensible pick for people with multiple food sensitivities - but the price is steep for a form that is not proven to outperform plain pyridoxine HCl.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
Solgar Pyridoxal-5-Phosphate (P5P) 50 mg
Solgar$15.99 ÷ 50 days at 50mg/day (1 serving × 50mg)
A vegan, kosher P5P, but the small bottle and lack of independent certification make it a weaker pick than the certified or bulk options - and it is still the non-trial P5P form. As of this review its Amazon listing was unavailable.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
NOW Foods P-5-P 50 mg (with magnesium)
NOW Foods$13.46 ÷ 90 days at 50mg/day (1 serving × 50mg)
A P5P-plus-magnesium combination rather than a standalone B6. Fine if you specifically want that pairing, but for B6 alone it dilutes the picture, and P5P is still not the form the efficacy trials used.
Prices checked 2026-07-07. Cost shown is per clinically effective daily dose, not per pill.
Full Comparison
| Category | Nature Made Vitamin B6 100 mg Nature Made | NOW Foods Vitamin B-6 (Pyridoxine HCl) 100 mg NOW Foods | Nutricost Vitamin B6 (Pyridoxine HCl) 100 mg Nutricost | Thorne Pyridoxal 5'-Phosphate (P5P) Thorne | Pure Encapsulations P5P 50 Pure Encapsulations | Solgar Pyridoxal-5-Phosphate (P5P) 50 mg Solgar | NOW Foods P-5-P 50 mg (with magnesium) NOW Foods |
|---|---|---|---|---|---|---|---|
| Brand Score | 90/100Winner | 84/100 | 82/100 | 82/100 | 79/100 | 74/100 | 72/100 |
| Dosing & Form | 25/25Winner | 25/25 | 25/25 | 21/25 | 21/25 | 21/25 | 17/25 |
| Purity | 25/25Winner | 19/25 | 18/25 | 23/25 | 20/25 | 16/25 | 19/25 |
| Value | 20/25 | 21/25 | 22/25Winner | 15/25 | 13/25 | 17/25 | 18/25 |
| Transparency | 20/25 | 19/25 | 17/25 | 23/25 | 25/25Winner | 20/25 | 18/25 |
| Cost/Day | $0.10 | $0.05 | $0.03Winner | $0.11 | $0.22 | $0.32 | $0.15 |
| Dose/Serving | 100mg | 100mg | 100mg | 34mg | 33mg | 50mg | 50mg |
| Form | pyridoxine HCl tablet | pyridoxine HCl veg capsule | pyridoxine HCl capsule | pyridoxal 5'-phosphate (P5P) capsule | pyridoxal 5'-phosphate (P5P) hypoallergenic capsule | pyridoxal-5-phosphate (P5P) tablet | P5P + magnesium bisglycinate veg capsule |
| Third-Party Tested | ✓ Yes | ✓ Yes | ✓ Yes | ✓ Yes | ✓ Yes | No | ✓ Yes |
| Proprietary Blend | No | No | No | No | No | No | No |
Frequently Asked Questions
How much vitamin B6 is safe to take?
The adult tolerable upper intake level (UL) is 100 mg/day, and that is the number to respect. B6 is unusual among water-soluble vitamins in that excess is not simply flushed out harmlessly - chronic intake above the ceiling can cause sensory nerve damage. The catch is that many standalone B6 products are dosed at exactly 100 mg in a single capsule, so if you also take a B-complex or multivitamin that contains B6, you can exceed the limit without realizing it. Always add up your total from every supplement you take.
Is P5P better than regular pyridoxine (pyridoxine HCl)?
Not based on the evidence. P5P (pyridoxal 5'-phosphate) is the active coenzyme form, and it is often marketed as better absorbed - but that claim is not backed by trials. Your liver readily converts plain pyridoxine into P5P on its own, and the efficacy studies for premenstrual symptoms and pregnancy nausea used pyridoxine HCl, not P5P. P5P also costs more. Importantly, both forms share the identical neuropathy ceiling, so paying up for P5P does not buy you a safer or more effective product for the uses that matter.
Does vitamin B6 help with PMS?
There is reasonable support for it. A systematic review of nine randomized trials (about 940 women) found B6 at up to 100 mg/day outperformed placebo for premenstrual symptoms, with an odds ratio around 2.3 in its favor. The important caveat, which the review authors themselves flagged, is that most of those trials were low quality, so the finding is suggestive rather than definitive. Because B6 is inexpensive and the trial dose (up to 100 mg/day) stays at the safety ceiling, it is a reasonable option to try for a few cycles, but keep the dose capped.
Can I take vitamin B6 for pregnancy nausea?
Yes, and it is actually a first-line recommendation - but coordinate it with your obstetrician. A randomized trial in 342 women found pyridoxine at 30 mg/day significantly reduced nausea versus placebo, and ACOG names vitamin B6 (10-25 mg every 6-8 hours), alone or combined with doxylamine, as a first-line treatment for nausea and vomiting of pregnancy. The dose stays low and well under the ceiling. Because you are pregnant, this is a decision to make with your clinician rather than on your own, both for the dose and for whether to pair it with doxylamine.
Does vitamin B6 lower cholesterol or protect the heart?
No. B6 does reliably lower homocysteine, a blood marker that was once thought to drive heart disease, and that is where the heart-health marketing comes from. But when it was actually tested, the NORVIT trial gave a folic acid plus B6 plus B12 combination, successfully lowered homocysteine, and produced no cardiovascular benefit - with a trend toward harm. This pattern holds across multiple trials: B6 moves the number on the lab report, not the rate of actual heart events. Do not take B6 as a heart supplement.
What are the signs of taking too much B6?
The hallmark is a sensory neuropathy: tingling, numbness, burning sensations, and an unsteady gait (sensory ataxia), usually starting in the hands and feet. This was first documented in a 1983 case series at very high doses (about 2-6 g/day), but subsequent reports describe nerve symptoms at chronic intakes as low as roughly 100-200 mg/day. Symptoms typically improve after stopping the supplement, though recovery can be slow and is not always complete. If you notice new tingling or numbness and take B6, review your total intake across all your supplements and speak with your doctor.
Related Reading
Sources
- Wyatt KM, Dimmock PW, Jones PW, Shaughn O'Brien PM. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ. 1999;318(7195):1375-1381.
- Vutyavanich T, Wongtra-ngan S, Ruangsri R. Pyridoxine for nausea and vomiting of pregnancy: a randomized, double-blind, placebo-controlled trial. Am J Obstet Gynecol. 1995;173(3 Pt 1):881-884.
- Bonaa KH, Njolstad I, Ueland PM, et al. Homocysteine lowering and cardiovascular events after acute myocardial infarction (NORVIT). N Engl J Med. 2006;354(15):1578-1588.
- Spooner GR, Desai HB, Angel JF, Reeder BA, Donat JR. Using pyridoxine to treat carpal tunnel syndrome. Randomized control trial. Can Fam Physician. 1993;39:2122-2127.
- Schaumburg H, Kaplan J, Windebank A, et al. Sensory neuropathy from pyridoxine abuse. A new megavitamin syndrome. N Engl J Med. 1983;309(8):445-448.
- NIH Office of Dietary Supplements. Vitamin B6 Fact Sheet for Health Professionals.
Scores and tiers are our independent opinion, formed by applying a published rubric to label data, third-party certifications, and the research record. They are not statements of objective fact about a product and not a lab test. Where we report a brand-specific fact, it comes from a cited source or a public certification; where verification is missing, we say so rather than assume a result.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult with a qualified healthcare professional before starting any supplement regimen.