Vitamin B6

Pyridoxine, pyridoxal and pyridoxamine (vitamin B6) · also called Vitamina B6, piridoxina, PLP (active form)

Vitamin B6 is an essential water-soluble vitamin the body uses for nerves, red blood cells, antibodies and breaking down protein. Fish, poultry, potatoes, bananas and chickpeas are good sources. Research on pills is limited and mostly low certainty, for pregnancy sickness and premenstrual symptoms. Too much from pills can damage nerves, so ask a doctor or pharmacist first.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Vitamin B6

Vitamin B6 is an essential vitamin found in many foods. It is needed for nerves, blood and protein use. Pill trials are limited, and too much B6 can damage nerves.

What vitamin B6 is

Vitamin B6 is a water-soluble vitamin. MedlinePlus says water-soluble vitamins dissolve in water, so the body cannot store them and leftovers leave in the urine. It helps the body make antibodies, keep nerves working, make haemoglobin, break down protein and keep blood sugar in normal ranges.

B6 is really a family of forms: pyridoxine, pyridoxal and pyridoxamine. A review says only pyridoxal 5-phosphate (PLP) is the active form. The NHS says bacteria in the bowel can also make some B6.

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Where B6 comes from in food

MedlinePlus names tuna and salmon, bananas, legumes, beef and pork, nuts, poultry, whole grains and chickpeas, plus fortified cereals. The NHS adds peanuts, soya beans, wheatgerm, oats and milk.

USDA data, per portion: tuna, canned in water, 3 oz about 0.27 mg; farmed salmon, cooked, 3 oz about 0.55 mg; roasted chicken breast, half, about 0.52 mg; roasted pork loin, 3 oz about 0.47 mg; a medium baked potato with skin about 0.54 mg; a medium banana about 0.43 mg; cooked spinach, a cup, about 0.44 mg; cooked chickpeas, a cup, about 0.23 mg; cooked brown rice, a cup, about 0.25 mg; sunflower seeds, an ounce, about 0.38 mg.

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Low B6 and who is at risk

MedlinePlus says low B6 is uncommon. It can occur with kidney failure, liver disease or heavy alcohol use. Signs include confusion, depression, irritability, mouth and tongue sores and nerve damage in the hands and feet; a form of anaemia can also occur. These signs have many causes, so ask a doctor before assuming it is B6.

In a trial in people with rheumatoid arthritis and low blood B6, a month of pyridoxine pills corrected blood and urine markers of B6 status.

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What the research shows

Evidence for B6 pills is limited. For pregnancy sickness, a Cochrane review found only limited evidence and the best recent trial tested a two-ingredient medicine. For premenstrual syndrome, an old review found more women improved, but most trials were low quality. A trial in young adults found lower self-reported anxiety after a month of high-dose B6.

There was no benefit for memory in healthy older people, and B6 with B9 and B12 did not change heart attacks or deaths, with a small stroke difference. Observational studies link higher B6 to less bowel cancer, while one cohort links long-term high-dose pills to lung cancer in men. None of this shows that extra B6 helps people who already get enough.

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Too much vitamin B6

Large amounts of B6 over time can damage nerves. The NHS says 200 mg or more a day can cause loss of feeling in the arms and legs, which usually improves after stopping but can be permanent in a few cases. EFSA (2023) calls the link well established and based its upper level on it.

EFSA set an upper level of 12 mg a day for adults, including pregnant and breastfeeding women. The NHS advises not taking more than 10 mg a day in supplements unless a doctor says so. A case report described nerve damage and a very high blood level in a man who took only a multivitamin with 6 mg of B6. These are regulator statements, not advice to take B6. The US upper limit could not be read.

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Food versus pills

Almost all trial results are for pyridoxine pills. Foods supply B6 along with protein and other nutrients, and no trial compared food B6 with pills. The NHS says most people can get what they need from a varied diet. This page gives no amounts to take; if you wonder about your own needs, ask a doctor, pharmacist or dietitian.

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At a glance

Traditional uses history, not proof

An essential vitamin from food
Sold as pills for premenstrual symptoms, pregnancy sickness and mood

Studied for research

Nutrient role and low B6, high certainty
Nausea and vomiting in early pregnancy, low certainty
Premenstrual syndrome, low certainty
Anxiety in young adults, low certainty
Heart attack and stroke (with B9 and B12), mixed
Memory in older people and carpal tunnel, insufficient evidence
Lung cancer in men taking long-term pills, evidence against benefit

Main compounds

Pyridoxine
Pyridoxal
Pyridoxamine
Pyridoxal 5-phosphate (PLP, the active form)

Common forms

Food sources (fish, poultry, potatoes, bananas, legumes, fortified cereals)
Single-vitamin pills, B-complex and multivitamins
Doxylamine plus pyridoxine, a two-ingredient medicine for pregnancy sickness

Research links: 2023 EFSA opinion: upper intake level for vitamin B6 · 2015 Cochrane review: nausea and vomiting in early pregnancy (41 trials) · 1999 review: vitamin B6 for premenstrual syndrome (9 trials) · 2017 Cochrane review: homocysteine-lowering vitamins and heart events · 2023 review: vitamin B6 and peripheral neuropathy · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Vitamin B6 (a group of related compounds: pyridoxine, pyridoxal and pyridoxamine, and their phosphate forms)
Common names: Vitamin B6 (English); Pyridoxine (English); Pyridoxal (English); Pyridoxamine (English); Vitamina B6 (Spanish); Piridoxina (Spanish)
Family or group: Water-soluble vitamin of the B group. MedlinePlus says water-soluble vitamins dissolve in water, so the body cannot store them and leftovers leave in the urine.
Look-alikes and adulterants: Name: Vitamin B12 and folate (B9); Note: Other B vitamins often combined with B6 in pills and in trials; each has its own page.
Sustainability and conservation: Not assessed.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Pyridoxine PubChem 1054	vitamin B6 vitamer	Not read from a source.	The form usually sold in supplements and tested in trials. ^{10 7}	Human data
Pyridoxal PubChem 1050	vitamin B6 vitamer	Not read from a source.	One of the three natural forms of B6. ¹⁰	Human data
Pyridoxamine PubChem 1052	vitamin B6 vitamer	Not read from a source.	One of the three natural forms of B6. ¹⁰	Human data
Pyridoxal 5-phosphate (PLP) PubChem 1051	active coenzyme form	Not read from a source.	A review says only PLP is the biologically active form, and blood PLP is used to judge B6 status. ^{13 2}	Human data

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Enzyme helper (coenzyme) for many reactions	Not stated in the abstracts read	A review states PLP is the biologically active form of B6 and takes part in many biochemical processes. ¹³	Human data
Homocysteine remethylation and one-carbon metabolism	Not stated	A Cochrane review says B6 is an essential cofactor in recycling homocysteine, and that deficiency is linked with higher blood homocysteine. ⁷	Human data
GABA synthesis and nerve inhibition	Not stated	The authors of a 2022 trial link their result on anxiety to B6 helping make the calming brain chemical GABA. This is their interpretation. ⁴	Human data

Absorption, metabolism and elimination

Absorption: Not read from a source.
Distribution: Not read from a source.
Metabolism: Pyridoxine and other forms are turned into the active form PLP (stated in a review).
Elimination: MedlinePlus says leftover water-soluble vitamins leave the body in urine.
Bioavailability: Not read from a source.

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Isolated compounds versus whole extracts

Food B6 and pill B6 are not the same exposure. Foods bring protein, fibre and other nutrients, and the amounts differ greatly. The NHS says most people can get what they need from a varied diet, and bowel bacteria also make some B6. Almost all trial results are for pyridoxine pills; no trial compared food B6 with pills.

Nutritional composition

B6 content of foods is from USDA FoodData Central SR Legacy (April 2018 release), read 2026-10-26 from a saved local copy; values are per 100 g and per household portion, see the Food sources item and the study table.

12benefits and uses looked at

20studies and sources checked

High certaintybest evidence rating found

6lab markers tracked in trials

2 high certainty1 mixed findings4 low certainty1 very low certainty3 not enough evidence1 evidence against

What was looked at

The 12 benefits and uses checked for Vitamin B6, each with how strong the evidence is. Tap one to open it.

Essential nutrient and low B6High certainty
Food sources of vitamin B6High certainty
Nausea and vomiting in early pregnancyLow certainty
Premenstrual syndrome (PMS)Low certainty
Memory, thinking and mood in older peopleNot enough evidence
Anxiety and low moodLow certainty
Heart attack and stroke (with B9 and B12)Mixed findings
Carpal tunnel syndromeNot enough evidence
Nerve damage (neuropathy) from other causesNot enough evidence
Colorectal cancer (observational)Very low certainty
Lung cancer risk (possible harm from long-term high-dose pills in men)Evidence against
Inflammation in rheumatoid arthritisLow certainty

Lab markers tracked in the studies

Blood B6 (pyridoxal 5-phosphate, PLP)Pregnancy sickness score (PUQE)Overall premenstrual symptom improvementStrokeLung cancer in menColorectal cancer risk

What is Vitamin B6 good for?

The main studied uses and how strong the human evidence is for each. Most results are for pills in small or older trials.

Essential nutrient and low B6High certaintyB6 helps make antibodies, keeps nerves working, helps make haemoglobin and breaks down protein. Low B6 is uncommon but can happen with kidney failure, liver disease or heavy alcohol use. In a trial in people with arthritis and low B6, pills corrected the blood markers. Food sources of vitamin B6High certaintyBy USDA data, 3 oz (85 g) of cooked farmed salmon has about 0.55 mg, a medium baked potato with skin about 0.54 mg, half a roasted chicken breast about 0.52 mg, a medium banana about 0.43 mg and a cup of cooked chickpeas about 0.23 mg. Fortified cereals may also contain B6. Nausea and vomiting in early pregnancyLow certaintyA 2015 Cochrane review of 41 trials found only limited evidence for B6. A 2023 trial of doxylamine plus pyridoxine found a modest gain and more small-for-gestational-age babies than placebo. Premenstrual syndrome (PMS)Low certaintyA 1999 review of 9 placebo-controlled trials (940 women) found improvement was more likely with B6 (odds ratio 2.32). The authors say most trials were of low quality. Anxiety and low moodLow certaintyIn a 2022 trial of 478 young adults, a month of high-dose B6 lowered self-reported anxiety; depression fell only as a trend. Heart attack and stroke (with B9 and B12)Mixed findingsA 2017 Cochrane review of 15 trials (71,422 people) found no change in heart attack or death and a small stroke difference (RR 0.90). It does not separate B6 from folic acid and B12. Memory and mood in older peopleNot enough evidenceA 2003 Cochrane review found two small trials (109 healthy older people) and no benefit for memory or mood. There were no trials in people with dementia. Carpal tunnel syndromeNot enough evidenceA 2007 review calls the effectiveness of B6 for carpal tunnel syndrome controversial. No trial results were read. Nerve damage from other causesNot enough evidenceTwo reviews found no good evidence that B6 treats neuropathy, and no data for B6 on its own. Colorectal cancer (observational)Very low certaintyA 2023 meta-analysis of 28 observational studies linked higher B6 intake to lower bowel cancer risk (OR 0.80). It cannot show that pills prevent cancer. Lung cancer (possible harm in men)Evidence againstIn a US cohort of 77,118 adults, men with long-term high-dose single B6 pills had a hazard ratio of 1.82 for lung cancer. It is an association from one study, not proof. Inflammation in rheumatoid arthritisLow certaintyIn a small trial, a month of B6 corrected B6 status in people with arthritis but did not change immune-cell inflammation markers.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Essential nutrient and low B6

High certainty

Vitamin B6 is a water-soluble vitamin the body cannot store. MedlinePlus says it helps make antibodies, keeps nerves working, helps make haemoglobin, breaks down proteins and keeps blood sugar in normal ranges. Low B6 is uncommon. It can happen with kidney failure, liver disease or heavy alcohol use, and can cause confusion, low mood, mouth sores and nerve damage.

5 studiesVitamin B6 as a nutrient from food and from pyridoxine pills; forms a…

Studies, doses and limits

What the trials found

MedlinePlus lists the jobs of B6 and the signs of deficiency. The NHS says B6 helps the body use and store energy from protein and carbohydrate and form haemoglobin, and that bacteria in the bowel can also make it. A review says only PLP is the biologically active form, and that a blood PLP above 30 nmol/L shows adequate status. In a placebo-controlled trial in people with rheumatoid arthritis and low blood B6, a month of pyridoxine pills corrected blood and urine markers of B6 status. In two small trials in healthy older people, pills raised blood B6 markers in the one trial that measured them.

Results

B6 is essential, and a shortage causes real problems. Pills raise blood B6 in people who are low. No evidence was read that extra B6 helps people who already get enough.

Effect sizes as reported

No effect sizes apply: these are nutrient roles and status markers.

Why this rating

High that B6 is essential and that deficiency has recognised signs (MedlinePlus, NHS, reviews). Not a trial result for any health benefit.

Form and dose studied

Vitamin B6 as a nutrient from food and from pyridoxine pills; forms are not compared here.

Who was studied

General population. People with kidney failure, liver disease or heavy alcohol use are named by MedlinePlus as more likely to be low.

Limits

The health pages are summaries. The trial that corrected status was small, short and in one disease group.

Why researchers looked

People ask whether they get enough B6 and whether pills do more than food.

Traditional use

B6 is an essential nutrient. Its roles in the body are well established; that is different from showing that extra pills treat a condition.

Proposed mechanism Established nutrition

Vitamin B6 in its active form, pyridoxal 5-phosphate (PLP), works as a helper for many enzymes. This is established biochemistry stated in a review.

A proposed mechanism does not show that the effect happens in people.

Too much B6 from pills can damage nerves; see the Safety tab.

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Food sources of vitamin B6

High certainty

B6 is found in fish, meat, poultry, potatoes, bananas, legumes, nuts, seeds and whole grains. By USDA data, 3 oz (85 g) of cooked farmed salmon has about 0.55 mg, a medium baked potato with skin about 0.54 mg, half a roasted chicken breast about 0.52 mg, a medium banana about 0.43 mg and a cup of cooked chickpeas about 0.23 mg. Fortified cereals can also contain B6.

3 studiesFoods only; this is not a recommendation to eat any food or to take B…

Studies, doses and limits

What the trials found

MedlinePlus names tuna and salmon, banana, legumes, beef and pork, nuts, poultry, whole grains, chickpeas and fortified breads and cereals. The NHS names pork, poultry, some fish, peanuts, soya beans, wheatgerm, oats, bananas, milk and some fortified breakfast cereals. No trial was read that compares food B6 with pills for health results.

Results

Many everyday foods carry B6. Tuna, salmon, poultry, pork, potatoes, bananas, chickpeas and seeds all contribute.

Effect sizes as reported

USDA B6, per 100 g and per portion: tuna, light, canned in water, drained 0.319 mg and about 0.27 mg per 3 oz; Atlantic salmon, farmed, cooked 0.647 mg and about 0.55 mg per 3 oz; chicken breast, roasted 0.600 mg and about 0.52 mg per half breast (86 g); pork loin, lean, roasted 0.552 mg and about 0.47 mg per 3 oz; baked potato with skin 0.311 mg and about 0.54 mg per medium potato (173 g); banana 0.367 mg and about 0.43 mg per medium banana (118 g); spinach, cooked 0.242 mg and about 0.44 mg per cup; chickpeas, cooked 0.139 mg and about 0.23 mg per cup; brown rice, cooked 0.123 mg and about 0.25 mg per cup; sunflower seed kernels 1.345 mg and about 0.38 mg per ounce.

Why this rating

High that foods contain these amounts (USDA tables). How much the body absorbs from each food was not measured in the sources read.

Form and dose studied

Foods only; this is not a recommendation to eat any food or to take B6.

Who was studied

General adult diet.

Limits

SR Legacy values are from a 2018 release. Cooking, storage, brand and growing conditions change B6 content. Absorption was not measured.

Why researchers looked

Many people want to know where B6 comes from in food.

Traditional use

B6 is an essential vitamin. Naming good food sources is nutrition information, not a treatment claim.

Proposed mechanism Nutrient database

These are nutrient amounts in foods taken from USDA tables.

A proposed mechanism does not show that the effect happens in people.

Eat a varied diet; see the Safety tab for B6 excess from pills.

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Nausea and vomiting in early pregnancy

Low certainty

A 2015 Cochrane review of 41 trials found only limited evidence for vitamin B6, or for B6 combined with doxylamine, in mild or moderate pregnancy sickness. A 2023 trial of the two-ingredient medicine in 352 women found a modest gain, and more small-for-gestational-age babies than placebo.

2 studiesPyridoxine tablets alone, or doxylamine plus pyridoxine as a medicine…

Studies, doses and limits

What the trials found

The Cochrane review included trials of many treatments, including vitamin B6. It could not pool most results because the trials were so different, and found no high-quality evidence for any one treatment. In the 2023 trial, women with moderate to severe sickness took doxylamine plus pyridoxine or placebo for 14 days. Their sickness score fell by about 1 point more than on placebo, a modest gain. Babies born small for their age were more common with the medicine.

Results

Some benefit is possible, but the evidence is limited and the one large trial tested a two-ingredient medicine, not B6 alone.

Effect sizes as reported

Cochrane 2015: 41 trials, 5449 women, no pooled effect. 2023 trial: PUQE score difference -1.0 (95% CI -1.6 to -0.4); small for gestational age odds ratio 3.8 (1.0 to 14.1).

Why this rating

Limited, mixed-quality trials; the largest recent trial used doxylamine-pyridoxine together, and raised a borderline safety signal.

Form and dose studied

Pyridoxine tablets alone, or doxylamine plus pyridoxine as a medicine; they were not compared head to head.

Who was studied

Women in early pregnancy. Hyperemesis gravidarum (severe sickness) was excluded from the Cochrane review.

Limits

The two-ingredient result cannot be applied to B6 alone. The small-baby finding is from one trial with a wide range.

Why researchers looked

Pregnancy sickness is common and B6 is one of the best-known options.

Traditional use

Doctors have long used B6, alone or with doxylamine, for pregnancy sickness. This page reports only what the trials found.

Proposed mechanism Hypothesis

How B6 might ease nausea is not known; no mechanism was read.

A proposed mechanism does not show that the effect happens in people.

Pregnancy sickness should be managed with a doctor or midwife. See the Safety tab on pregnancy.

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Premenstrual syndrome (PMS)

Low certainty

A 1999 review of 9 placebo-controlled trials in 940 women found women taking B6 were more likely to report improvement, including in low mood. The authors say most trials were of low quality.

1 studiesVitamin B6 (pyridoxine) pills. The trials used doses far above the of…

Studies, doses and limits

What the trials found

The review pooled 9 published placebo-controlled trials. Improvement in overall symptoms was more likely with B6 than placebo (odds ratio 2.32). Improvement in depressive symptoms was also more likely (odds ratio 1.69, 4 trials, 541 women). The authors limit their conclusions because of the low quality of most trials. No newer review of B6 alone was read.

Results

B6 may help some women with premenstrual symptoms, but the trials were weak and old.

Effect sizes as reported

Overall symptoms: odds ratio 2.32 (95% CI 1.95 to 2.54). Depressive symptoms: odds ratio 1.69 (1.39 to 2.06).

Why this rating

Low-quality trials from before 1999, pooled without a formal quality rating.

Form and dose studied

Vitamin B6 (pyridoxine) pills. The trials used doses far above the official upper limits stated on the Safety tab.

Who was studied

Women with premenstrual syndrome.

Limits

Old review; trial quality low; no funding information in the abstract.

Why researchers looked

B6 is among the most studied vitamins for premenstrual symptoms.

Traditional use

B6 has long been sold for premenstrual symptoms. This page reports only the trial review.

Proposed mechanism Hypothesis

No mechanism was read for this use.

A proposed mechanism does not show that the effect happens in people.

The trial doses are well above the current European and UK upper limits; see the Safety tab.

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Memory, thinking and mood in older people

Not enough evidence

A 2003 Cochrane review found only two small trials of B6 in healthy older people (109 people) and no benefit for memory, thinking or mood. It found no trials in people with dementia.

1 studiesPyridoxine pills; the trials used different amounts.

Studies, doses and limits

What the trials found

The review found two double-blind placebo-controlled trials. One gave B6 to older women for 5 weeks, the other to men aged 70 to 79 for 12 weeks. Neither showed a significant difference from placebo for thinking or mood. No side effects were reported. Neither trial measured homocysteine.

Results

No benefit shown in healthy older people; too little research to rule one out.

Effect sizes as reported

No significant difference in cognition or mood in either trial.

Why this rating

Two small, short trials from before 2003; none in people with memory loss.

Form and dose studied

Pyridoxine pills; the trials used different amounts.

Who was studied

Healthy people aged 65 and over.

Limits

Very small evidence base; old search date.

Why researchers looked

B6 helps make brain chemicals and lowers homocysteine, so it has been tried for memory.

Traditional use

B6 is sometimes sold for memory. This page reports only the trial review.

Proposed mechanism Established physiology

B6 takes part in making brain chemical messengers; whether pills change thinking was tested in the trials.

A proposed mechanism does not show that the effect happens in people.

Long-term high-dose B6 can damage nerves.

⁷

Anxiety and low mood

Low certainty

In a 2022 trial of 478 young adults, a month of high-dose B6 lowered self-reported anxiety and showed a trend toward lower depression. Other tests did not change reliably.

1 studiesHigh-dose B6 pills (amount not in the abstract).

Studies, doses and limits

What the trials found

This double-blind trial gave young adults high-dose B6 or B12 or placebo for one month. Anxiety was reported by 265 people and depression by 146. B6 reduced self-reported anxiety. Depression fell only as a trend. The abstract does not say participants had an anxiety disorder, and gives no numbers.

Results

A small possible effect on self-reported anxiety in young adults after a month; not tested over the long term.

Effect sizes as reported

No numbers in the abstract.

Why this rating

One trial; short; self-reported scores; the dose is high, and long-term safety of high-dose B6 was not tested.

Form and dose studied

High-dose B6 pills (amount not in the abstract).

Who was studied

Young adults.

Limits

Single trial; the amount used is not stated in the abstract; safety at that amount over time is unknown.

Why researchers looked

B6 helps make GABA, a calming brain chemical.

Traditional use

B6 is sometimes sold for stress. This page reports only the trial.

Proposed mechanism Authors interpretation

The authors link the result to B6 helping make GABA; that is their interpretation.

A proposed mechanism does not show that the effect happens in people.

High doses taken for long can damage nerves; see the Safety tab.

⁴

Heart attack and stroke (with B9 and B12)

Mixed findings

A 2017 Cochrane review of 15 trials (71,422 people) found B vitamin supplements that lower homocysteine did not change heart attacks or deaths, and gave a small difference for stroke. The review does not separate B6 from folic acid and B12.

1 studiesB6, B9 or B12 pills alone or together.

Studies, doses and limits

What the trials found

The review pooled 15 randomised trials lasting 1 to 7.3 years. Heart attack: no difference. Death from any cause: no difference. Serious side effects: no clear difference. Stroke: a small difference favouring the supplements (4.3% versus 5.1%).

Results

No benefit for heart attack or death; a small stroke difference for B6, B9 and B12 supplements together, not shown for B6 alone.

Effect sizes as reported

Heart attack RR 1.02 (0.95 to 1.10). Death RR 1.01 (0.96 to 1.06). Stroke RR 0.90 (0.82 to 0.99). Serious adverse events RR 1.07 (1.00 to 1.14).

Why this rating

Cochrane rates the heart attack, death and stroke findings as high-quality, but they apply to B6, B9 and B12 together.

Form and dose studied

B6, B9 or B12 pills alone or together.

Who was studied

Adults with and without heart disease; end-stage kidney disease excluded.

Limits

Cannot say what B6 alone does; stroke difference is small.

Why researchers looked

B6, folic acid and B12 lower blood homocysteine, which was once thought to cause heart disease.

Traditional use

B vitamins were widely promoted for heart health. This page reports only the trial review.

Proposed mechanism Established physiology

B6 helps recycle homocysteine in the body; the trials tested whether lowering it prevents events.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab for excess B6.

⁸

Carpal tunnel syndrome

Not enough evidence

B6 is often used for carpal tunnel syndrome, but a 2007 review calls its effectiveness controversial. No trial results were read.

1 studiesB6 pills; amounts not stated here.

Studies, doses and limits

What the trials found

Only an abstract of a 2007 family-doctor review was read. It says effectiveness is controversial and that people should be watched for changes in symptoms, especially at high doses over long periods.

Results

No clear evidence of benefit was read.

Effect sizes as reported

No numbers in the abstract.

Why this rating

A short review with no trial data in the abstract.

Form and dose studied

B6 pills; amounts not stated here.

Who was studied

People with carpal tunnel syndrome.

Limits

The review says doses under 200 mg a day were unlikely to cause side effects; the 2023 EFSA opinion and the NHS do not agree.

Why researchers looked

Many people with hand numbness try B6 on their own.

Traditional use

B6 has long been used as a gentle or add-on treatment for carpal tunnel syndrome.

Proposed mechanism Hypothesis

No mechanism was read.

A proposed mechanism does not show that the effect happens in people.

High-dose B6 can itself cause numbness and nerve damage; see the Safety tab.

¹⁴

Nerve damage (neuropathy) from other causes

Not enough evidence

Two systematic reviews found no good evidence that B6 treats nerve damage from other causes, and no data on B6 given alone.

2 studiesPyridoxine; no dose comparison.

Studies, doses and limits

What the trials found

A 2023 review of 20 articles found low B6 can be seen in people with neuropathy but no firm proof it causes it, and no data on B6 as a single treatment. A 2014 review found inadequate evidence for routine pyridoxine in nerve disorders.

Results

The treatment role of B6 for neuropathy is not shown.

Effect sizes as reported

No numbers in the abstracts.

Why this rating

Two reviews of limited, mostly small reports.

Form and dose studied

Pyridoxine; no dose comparison.

Who was studied

People with peripheral neuropathy.

Limits

Low-quality evidence; results come only from combination vitamin treatments.

Why researchers looked

Low B6 can cause nerve damage, so B6 is tried for neuropathy of other kinds.

Traditional use

B6 is often tried for nerve symptoms.

Proposed mechanism Hypothesis

No mechanism was read.

A proposed mechanism does not show that the effect happens in people.

The same reviews link high B6 to a nerve problem; see the Safety tab.

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Colorectal cancer (observational)

Very low certainty

A 2023 meta-analysis of 28 observational studies found higher B6 intake and higher blood B6 linked to lower colorectal cancer risk. It cannot show that pills prevent cancer.

1 studiesDietary intake and blood levels, not pills.

Studies, doses and limits

What the trials found

The meta-analysis combined 20 cohort and 8 case-control studies. People with higher B6 intake had an odds ratio of 0.80 and those with higher blood PLP 0.54. These are links in observational studies and could reflect other differences between people.

Results

A link, not proof of prevention.

Effect sizes as reported

Intake OR 0.80 (0.68 to 0.94). Blood PLP OR 0.54 (0.35 to 0.84).

Why this rating

Observational studies can be confounded; no trial of B6 pills for cancer prevention was read.

Form and dose studied

Dietary intake and blood levels, not pills.

Who was studied

Adults in 28 studies.

Limits

Observational; confounding likely.

Why researchers looked

Researchers look for diet links to bowel cancer.

Traditional use

No traditional use.

Proposed mechanism Hypothesis

No mechanism was read.

A proposed mechanism does not show that the effect happens in people.

These links do not show that pills prevent cancer; see the lung cancer finding on this tab.

⁶

Lung cancer risk (possible harm from long-term high-dose pills in men)

Evidence against

A US cohort of 77,118 adults found long-term single B6 or B12 pills were linked to higher lung cancer risk in men, nearly double in the highest B6 group, and no link in women. This is an association, not proof.

1 studiesB6 and B12 from single supplements; multivitamins not linked.

Studies, doses and limits

What the trials found

In the VITAL cohort, men who averaged more than 20 mg a day of B6 from single pills for 10 years had a hazard ratio of 1.82 for lung cancer compared with non-users. B6 from multivitamins was not linked. The risk was higher in men who smoked. The authors conclude B vitamin pills are not protective and may be harmful.

Results

No protection against lung cancer, and a possible risk signal for men taking high-dose single B6 pills for years.

Effect sizes as reported

Highest B6 group in men: HR 1.82 (95% CI 1.25 to 2.65).

Why this rating

One observational cohort, so low confidence; it shows no protective effect and raises a signal that needs confirming.

Form and dose studied

B6 and B12 from single supplements; multivitamins not linked.

Who was studied

Adults 50 to 76 in the US.

Limits

Observational; self-reported use; not proof of cause.

Why researchers looked

Millions take B vitamin supplements, so a possible harm matters.

Traditional use

No traditional use.

Proposed mechanism Hypothesis

No mechanism was read.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab.

Inflammation in rheumatoid arthritis

Low certainty

In a small trial in people with rheumatoid arthritis and low B6, a month of B6 corrected B6 status but did not change inflammation markers made by immune cells.

1 studiesPyridoxine pills.

Studies, doses and limits

What the trials found

This double-blind placebo-controlled trial gave pyridoxine to people with arthritis and low B6 for 30 days. Status markers improved significantly. Pro-inflammatory cytokine production (TNF-alpha, IL-6) did not change.

Results

B6 corrected the deficiency but did not reduce this measure of inflammation.

Effect sizes as reported

No numbers in the abstract.

Why this rating

Small, short trial; the abstract does not give the number of people.

Form and dose studied

Pyridoxine pills.

Who was studied

People with rheumatoid arthritis and low B6.

Limits

Single small trial; no clinical outcome such as joint pain was measured in the abstract.

Why researchers looked

People with rheumatoid arthritis often have low B6.

Traditional use

No traditional use.

Proposed mechanism Hypothesis

No mechanism was read.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab for high-dose B6.

Connections to the rest of health

How Vitamin B6 connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Evidence status	Context	Studies
Balanced Nutrition	High certainty	Essential nutrient and low B6: Vitamin B6 is a water-soluble vitamin the body cannot store. MedlinePlus says it helps make antibodies, keeps nerves working, helps make haemoglobin, breaks down proteins and keeps blood sugar in normal ranges. Low B6 is uncommon. It can happen with kidney failure, liver disease or heavy alcohol use, and can cause confusion, low mood, mouth sores and nerve damage.	^{17 18 13 2 7}
Balanced Nutrition	High certainty	Food sources of vitamin B6: B6 is found in fish, meat, poultry, potatoes, bananas, legumes, nuts, seeds and whole grains. By USDA data, 3 oz (85 g) of cooked farmed salmon has about 0.55 mg, a medium baked potato with skin about 0.54 mg, half a roasted chicken breast about 0.52 mg, a medium banana about 0.43 mg and a cup of cooked chickpeas about 0.23 mg. Fortified cereals can also contain B6.	^{20 17 18}
Womens Wellness	Low certainty	Nausea and vomiting in early pregnancy: A 2015 Cochrane review of 41 trials found only limited evidence for vitamin B6, or for B6 combined with doxylamine, in mild or moderate pregnancy sickness. A 2023 trial of the two-ingredient medicine in 352 women found a modest gain, and more small-for-gestational-age babies than placebo. Premenstrual syndrome (PMS): A 1999 review of 9 placebo-controlled trials in 940 women found women taking B6 were more likely to report improvement, including in low mood. The authors say most trials were of low quality.	^{9 15 16}
Pregnancy Support	Low certainty	Nausea and vomiting in early pregnancy: A 2015 Cochrane review of 41 trials found only limited evidence for vitamin B6, or for B6 combined with doxylamine, in mild or moderate pregnancy sickness. A 2023 trial of the two-ingredient medicine in 352 women found a modest gain, and more small-for-gestational-age babies than placebo.	^{9 15}
Mood Balance	Low certainty	Premenstrual syndrome (PMS): A 1999 review of 9 placebo-controlled trials in 940 women found women taking B6 were more likely to report improvement, including in low mood. The authors say most trials were of low quality.	¹⁶
Memory Support	Not enough evidence	Memory, thinking and mood in older people: A 2003 Cochrane review found only two small trials of B6 in healthy older people (109 people) and no benefit for memory, thinking or mood. It found no trials in people with dementia.	⁷
Healthy Aging	Not enough evidence	Memory, thinking and mood in older people: A 2003 Cochrane review found only two small trials of B6 in healthy older people (109 people) and no benefit for memory, thinking or mood. It found no trials in people with dementia.	⁷
Stress Reduction	Low certainty	Anxiety and low mood: In a 2022 trial of 478 young adults, a month of high-dose B6 lowered self-reported anxiety and showed a trend toward lower depression. Other tests did not change reliably.	⁴
Mood Balance	Low certainty	Anxiety and low mood: In a 2022 trial of 478 young adults, a month of high-dose B6 lowered self-reported anxiety and showed a trend toward lower depression. Other tests did not change reliably.	⁴
Heart Health	Mixed findings	Heart attack and stroke (with B9 and B12): A 2017 Cochrane review of 15 trials (71,422 people) found B vitamin supplements that lower homocysteine did not change heart attacks or deaths, and gave a small difference for stroke. The review does not separate B6 from folic acid and B12.	⁸
Joint Support	Not enough evidence	Carpal tunnel syndrome: B6 is often used for carpal tunnel syndrome, but a 2007 review calls its effectiveness controversial. No trial results were read.	¹⁴
Preventive Wellness	Not enough evidence	Nerve damage (neuropathy) from other causes: Two systematic reviews found no good evidence that B6 treats nerve damage from other causes, and no data on B6 given alone.	^{10 5}
Preventive Wellness	Very low certainty	Colorectal cancer (observational): A 2023 meta-analysis of 28 observational studies found higher B6 intake and higher blood B6 linked to lower colorectal cancer risk. It cannot show that pills prevent cancer.	⁶
Preventive Wellness	Evidence against	Lung cancer risk (possible harm from long-term high-dose pills in men): A US cohort of 77,118 adults found long-term single B6 or B12 pills were linked to higher lung cancer risk in men, nearly double in the highest B6 group, and no link in women. This is an association, not proof.	¹
Joint Health	Low certainty	Inflammation in rheumatoid arthritis: In a small trial in people with rheumatoid arthritis and low B6, a month of B6 corrected B6 status but did not change inflammation markers made by immune cells.	²

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Nutrition	Biological association	High certainty	Studied for: Essential nutrient and low B6 Studied for: Food sources of vitamin B6	^{17 18 13 2 7 20}
Nervous System	Biological association	High certainty	Studied for: Essential nutrient and low B6 Studied for: Premenstrual syndrome (PMS)	^{17 18 13 2 7 16 4 14 10 5}
Digestive System	Biological association	High certainty	Studied for: Food sources of vitamin B6 Studied for: Nausea and vomiting in early pregnancy	^{20 17 18 9 15 6}
Reproductive System	Biological association	Low certainty	Studied for: Nausea and vomiting in early pregnancy Studied for: Premenstrual syndrome (PMS)	^{9 15 16}
Cardiovascular System	Biological association	Mixed findings	Studied for: Heart attack and stroke (with B9 and B12)	⁸
Musculoskeletal System	Biological association	Not enough evidence	Studied for: Carpal tunnel syndrome Studied for: Inflammation in rheumatoid arthritis	^{14 2}
Respiratory System	Biological association	Evidence against	Studied for: Lung cancer risk (possible harm from long-term high-dose pills in men)	¹
Immune System	Biological association	Low certainty	Studied for: Inflammation in rheumatoid arthritis	²

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Peripheral neuropathy	Adverse effect or risk	Documented risk	High B6 from supplements is linked to a mainly sensory nerve problem; EFSA bases its upper limit on it. Preparation or compound: Pyridoxine supplements	^{3 10 18}
Nausea and vomiting in pregnancy		Clinical trial evidence	Limited evidence for B6 and a modest gain for the two-ingredient medicine, with a baby-size signal. Preparation or compound: Doxylamine plus pyridoxine	^{9 15}
Lung cancer		Observational	A cohort linked high-dose long-term single B6 pills to higher lung cancer risk in men. Preparation or compound: Single B6 supplements in men	¹
Premenstrual syndrome		Preliminary	Women taking B6 were more likely to improve in low-quality trials. Preparation or compound: Pyridoxine pills	¹⁶

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Blood B6 (pyridoxal 5-phosphate, PLP)	Biological association	High certainty	Measured in trials: higher with B6 pills. A lab change is not the same as a health benefit.	^{2 7}
Pregnancy sickness score (PUQE)	Biological association	Low certainty	Measured in trials: lower with doxylamine-pyridoxine (modest). A lab change is not the same as a health benefit.	¹⁵
Overall premenstrual symptom improvement	Biological association	Low certainty	Measured in trials: more improvement with B6 (low-quality trials). A lab change is not the same as a health benefit.	¹⁶
Stroke	Biological association	Mixed findings	Measured in trials: slightly lower with B6, B9 and B12 supplements. A lab change is not the same as a health benefit.	⁸
Lung cancer in men	Biological association	Very low certainty	Measured in trials: higher in men with high 10-year B6 use. A lab change is not the same as a health benefit.	¹
Colorectal cancer risk	Biological association	Very low certainty	Measured in trials: lower with higher B6 intake (association). A lab change is not the same as a health benefit.	⁶

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Homocysteine	Preliminary mechanism	Human	B6 helps recycle homocysteine; trials of lowering it with B6, B9 and B12 found no change in heart attack and a small difference in stroke.	^{7 8}
Vitamin B12 and folate (B9)	Preliminary mechanism	Human	Studied together with B6 in homocysteine and cancer-risk research.	^{8 1}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Pyridoxine	Biological association	Human	The form usually sold in supplements and tested in trials.	^{10 7}
Pyridoxal	Biological association	Human	One of the three natural forms of B6.	¹⁰
Pyridoxamine	Biological association	Human	One of the three natural forms of B6.	¹⁰
Pyridoxal 5-phosphate (PLP)	Biological association	Human	A review says only PLP is the biologically active form, and blood PLP is used to judge B6 status.	^{13 2}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).

Evidence at a glance: what the research found for 12 outcomes

2High certainty

4Low certainty

1Very low certainty

1Mixed findings

3Not enough evidence

1Evidence against

Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.

Essential nutrient and low B6 5 studies High certainty Food sources of vitamin B6 3 studies High certainty Nausea and vomiting in early pregnancy 2 studies Low certainty Premenstrual syndrome (PMS) 1 study Low certainty Memory, thinking and mood in older people 1 study Not enough evidence Anxiety and low mood 1 study Low certainty Heart attack and stroke (with B9 and B12) 1 study Mixed findings Carpal tunnel syndrome 1 study Not enough evidence Nerve damage (neuropathy) from other causes 2 studies Not enough evidence Colorectal cancer (observational) 1 study Very low certainty Lung cancer risk (possible harm from long-term high-dose pills in men) 1 study · 77,118 people in trials Evidence against Inflammation in rheumatoid arthritis 1 study Low certainty

The evidence

The research centre for Vitamin B6. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing B6 summary, read MedlinePlus and NHS pages, re-checked food values in saved USDA FoodData Central data, and re-read PubMed abstracts for reviews, trials and case reports. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.

Study library: every study we checked 20

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Brasky 2017 Long-Term, Supplemental, One-Carbon Metabolism-Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort. J Clin Oncol · PMID 28829668 · DOI	Cohort study	77118 77,118 US adults aged 50 to 76 followed for lung cancer (808 cases)	Supplemental vitamin B6, B12 and folate from single pills and from multivitamins Supplement or food 10-year average daily dose from supplements 10-year average use · vs Non-users	In women there was no link. In men, B6 or B12 from single-vitamin pills (not multivitamins) was linked to a 30% to 40% higher lung cancer risk, and the highest 10-year average B6 group had nearly double the risk. The risk was higher in men who smoked. The authors conclude B vitamin supplements are not protective and may be harmful. Men with a 10-year average of more than 20 mg a day of B6: hazard ratio 1.82. (HR 1.82 (95% CI 1.25 to 2.65)) Methods, limits and funding Outcomes: Lung cancer Limitations: Observational, so it cannot prove cause; one cohort; self-reported use; men only for the signal. Funding and conflicts: Not stated in the abstract. Read: abstract
Chiang 2005 Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis. Arthritis Res Ther · PMID 16277693 · DOI	Randomised controlled trial	People with rheumatoid arthritis whose blood B6 (pyridoxal-5-phosphate) was below the 25th percentile of a reference cohort; number not given in the abstract	Pyridoxine (vitamin B6) supplement Supplement or food 50 mg a day 30 days · vs Placebo	A month of pyridoxine significantly improved the blood and urine markers of B6 status, whatever the starting level. It did not change pro-inflammatory cytokine production. The authors suggest people with rheumatoid arthritis may need more B6 than healthy people. Significant improvement in plasma and red-cell PLP, AST activity coefficient, urinary 4-pyridoxic acid and xanthurenic acid; no change in cytokine production. (Not given in the abstract) Methods, limits and funding Outcomes: Blood and urine markers of B6 status; inflammation markers (TNF-alpha, IL-6) Limitations: Small, short, and in people with one disease; number of people not in the abstract. Funding and conflicts: Supported by US government research funds (NIH); no competing interests stated in the abstract. Read: abstract
EFSA Panel on Nutrition 2023 Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA J · PMID 37207271 · DOI	Regulatory opinion	Review of human and animal evidence by the European Food Safety Authority	Vitamin B6 intake from food and supplements Supplement or food	Peripheral neuropathy is the main harm and the basis for the limit. The Panel set an upper level of 12 mg a day for adults, including pregnant and breastfeeding women. For children it gave 2.2 to 2.5 mg a day (4 to 11 months), 3.2 to 4.5 mg (1 to 6 years) and 6.1 to 10.7 mg (7 to 17 years). EU populations are unlikely to exceed it except regular users of food supplements with high B6. Upper level 12 mg a day (adults). A reference point of 50 mg a day from a case-control study; a dog study LOAEL of 50 mg per kg body weight a day. (Not applicable) Methods, limits and funding Outcomes: Safe upper intake level Limitations: No lowest-observed-effect level could be set from human data; limits rest on an uncertainty factor. This is a regulator statement, not advice to take B6. Funding and conflicts: Independent EU agency opinion. Read: abstract
Field 2022 High-dose Vitamin B6 supplementation reduces anxiety and strengthens visual surround suppression. Hum Psychopharmacol · PMID 35851507 · DOI	Randomised controlled trial	478 478 young adults recruited over five linked phases (anxiety scores in 265, depression scores in 146); the abstract does not say they had an anxiety disorder	High-dose vitamin B6 (or B12) supplements Supplement or food High dose (amount not given in the abstract) 1 month · vs Placebo	B6 lowered self-reported anxiety, and there was a trend toward lower depression and stronger visual surround suppression. Other tests were not reliably changed. B12 gave trends only. No numbers in the abstract. (Not given in the abstract) Methods, limits and funding Outcomes: Self-reported anxiety and depression; sensory tests linked to nerve inhibition Limitations: One month only; self-reported scores; young adults; long-term safety of high-dose B6 was not tested. Funding and conflicts: No conflicts of interest declared. Read: abstract
Ghavanini 2014 Revisiting the evidence for neuropathy caused by pyridoxine deficiency and excess. J Clin Neuromuscul Dis · PMID 25137514 · DOI	Systematic review	Published reports of neuropathy from too little or too much pyridoxine	Pyridoxine (vitamin B6) Supplement or food	Very low daily intakes are enough to prevent neuropathy. There is inadequate evidence for routine pyridoxine in nerve disorders. The authors say pyridoxine above 50 mg a day for a long time may be harmful and should be discouraged. No numbers in the abstract. (Not applicable) Methods, limits and funding Outcomes: Neuropathy from deficiency and from excess; use as a treatment Limitations: Based on limited data. Funding and conflicts: Not stated in the abstract. Read: abstract
Lai 2023 Association Between Vitamin B6 and the Risk of Colorectal Cancer: A Meta-analysis of Observational Studies. Nutr Cancer · PMID 36961108 · DOI	Meta analysis observational	28 observational studies (20 cohort, 8 case-control); people followed for colorectal cancer	Vitamin B6 from food and supplements, and blood levels of pyridoxal-5-phosphate (PLP) Supplement or food · vs Lowest versus highest intake or blood level	Higher B6 intake and higher blood PLP were each linked to lower colorectal cancer risk. The studies are observational, so they cannot show cause. Intake odds ratio 0.80; blood PLP odds ratio 0.54. (Intake 0.68 to 0.94; blood PLP 0.35 to 0.84) Methods, limits and funding Outcomes: Colorectal cancer risk Limitations: Observational; people with higher B6 differ from others in diet and habits; does not show that taking pills lowers risk. Funding and conflicts: Not stated in the abstract. Read: abstract
Malouf 2003 The effect of vitamin B6 on cognition. Cochrane Database Syst Rev · PMID 14584010 · DOI	Systematic review meta analysis	109 2 double-blind trials in healthy older people (women aged 65 to 92 for 5 weeks; men aged 70 to 79 for 12 weeks); no trials in people with dementia or cognitive decline	Vitamin B6 (pyridoxine) supplements Supplement or food 75 mg a day in the women trial; 20 mg a day in the men trial 5 weeks and 12 weeks · vs Placebo	No statistically significant benefit for mood or thinking in either trial. In the men trial the supplement raised blood markers of B6 status. No adverse effects were reported. No trial measured homocysteine. No significant difference in cognition or mood. Plasma pyridoxal-5-phosphate in the men trial: weighted mean difference 238 (units not given in the abstract). (Plasma PLP difference 238 (95% CI 211.58 to 264.42)) Methods, limits and funding Outcomes: Cognition, mood, blood B6 status, adverse events Limitations: Only two small, short trials; search date 2003; none in people with memory problems. Funding and conflicts: Not stated in the abstract. Read: abstract
Marti-Carvajal 2017 Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev · PMID 28816346 · DOI	Systematic review meta analysis	71422 15 randomised trials, follow-up 1 to 7.3 years, people with and without heart disease (end-stage kidney disease excluded)	Vitamin B6, B9 (folic acid) or B12 supplements, alone or combined (B6 not separated from the others) Supplement or food Varied by trial 1 to 7.3 years · vs Placebo or low dose	No difference in heart attack or death from any cause. A small difference favouring the supplements for stroke. No difference in serious adverse events, though the range just reached 1.00. The review does not separate vitamin B6 from folic acid and B12. Heart attack RR 1.02; death RR 1.01; stroke RR 0.90; serious adverse events RR 1.07. (Heart attack 0.95 to 1.10; death 0.96 to 1.06; stroke 0.82 to 0.99; serious adverse events 1.00 to 1.14) Methods, limits and funding Outcomes: Heart attack, stroke, death from any cause, serious adverse events Limitations: Cannot say what B6 alone does; most of the effect on stroke may come from the other vitamins; search ended June 2017. Funding and conflicts: Cochrane review. One author reported unrelated paid workshops for drug companies in 2004 and 2007. Read: abstract
Matthews 2015 Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev · PMID 26348534 · DOI	Systematic review meta analysis	5449 41 randomised trials in women up to 20 weeks pregnant (hyperemesis gravidarum excluded)	Many treatments including vitamin B6, doxylamine-pyridoxine, ginger, acupressure and anti-sickness drugs Supplement or food Varied by trial Varied by trial · vs Placebo or other treatments	There was only limited evidence from trials to support vitamin B6, doxylamine-pyridoxine and other anti-sickness drugs for mild or moderate nausea and vomiting. Results could not be pooled for most outcomes. The authors found a lack of high-quality evidence for any one treatment, and said this is not the same as saying the treatments do not work. No pooled effect size (results could not be combined). (Not applicable) Methods, limits and funding Outcomes: Nausea, vomiting and retching in early pregnancy Limitations: Trials differed too much to pool; little information on harms to mother or baby; quality mixed; almost half did not report all planned outcomes. Funding and conflicts: Authors declare no interests in the abstract. Read: abstract
Muhamad 2023 The Role of Vitamin B6 in Peripheral Neuropathy: A Systematic Review. Nutrients · PMID 37447150 · DOI	Systematic review	20 published articles on B6 and nerve damage (neuropathy)	Vitamin B6 (pyridoxine), high levels and low levels Supplement or food Varied Varied	High B6 levels, usually from supplements, may cause a mainly sensory, axonal neuropathy that people report improves after stopping. There is no firm evidence that low B6 directly causes neuropathy. No data exist for B6 given alone as a treatment, only in vitamin combinations. B6 even in multivitamins has not been proven harmful at permitted daily doses in people who already have neuropathy. No numbers in the abstract. (Not applicable) Methods, limits and funding Outcomes: Nerve damage linked to high or low B6; B6 as a treatment Limitations: PubMed search only; mostly case reports and small studies. Funding and conflicts: No conflict of interest declared. Read: abstract
Nisar 1990 Exacerbation of isoniazid induced peripheral neuropathy by pyridoxine. Thorax · PMID 2166360 · DOI	Case report	1 A man with rheumatoid arthritis who developed nerve damage on the TB drug isoniazid	Pyridoxine plus isoniazid Supplement or food 150 mg a day of pyridoxine	The man got worse after isoniazid was stopped and pyridoxine given, and improved only once the pyridoxine was also stopped. The authors advise caution with pyridoxine for preventing or treating isoniazid neuropathy. One person. (Not applicable) Methods, limits and funding Outcomes: Neuropathy symptoms Limitations: A single 1990 case report. Funding and conflicts: Not stated in the abstract. Read: abstract
Paluszny 2023 Vitamin B6 Toxicity Secondary to Daily Multivitamin Use: A Case Report. Cureus · PMID 38098895 · DOI	Case report	1 A 73-year-old man with three years of worsening peripheral neuropathy	A daily multivitamin containing 6 mg of B6 Supplement or food 6 mg a day Daily	His blood B6 was 259.9 nmol/L (reference range 20 to 125). He took only a multivitamin with 6 mg of B6, below the new EFSA upper level of 12 mg. The authors call for more research on lower-dose B6. One person. (Not applicable) Methods, limits and funding Outcomes: Blood B6 level Limitations: One case; cause and effect not proven; other causes of neuropathy not detailed in the abstract. Funding and conflicts: No competing interests declared. Read: abstract
Reddy 2022 Preventing Vitamin B6-Related Neurotoxicity. Am J Ther · PMID 36608063 · DOI	Narrative review	Expert review of B6 status and neurotoxicity	Vitamin B6 (pyridoxine and pyridoxal 5-phosphate) Supplement or food	Only pyridoxal 5-phosphate (PLP) is the biologically active form. A plasma PLP above 30 nmol/L is said to show adequate status. The review says the link between raised pyridoxine and neuropathy is not well established and long-term safety at high doses needs trials. No effect sizes (review). (Not applicable) Methods, limits and funding Outcomes: Blood B6 status; neurotoxicity Limitations: A single-author opinion-style review; some statements are the author's view. Funding and conflicts: No conflicts of interest declared. Read: abstract
Ryan-Harshman 2007 Carpal tunnel syndrome and vitamin B6. Can Fam Physician · PMID 17872812	Narrative review	Review answering a family-doctor question on carpal tunnel syndrome	Vitamin B6 supplements Supplement or food	The review says B6 is often used as a gentle or add-on treatment but its effectiveness is controversial. It says doses under 200 mg a day were not likely to cause side effects, with monitoring for long use at high doses. No numbers in the abstract. (Not applicable) Methods, limits and funding Outcomes: Effectiveness and safety of B6 for carpal tunnel syndrome Limitations: A short review from 2007. Its view that doses under 200 mg a day are unlikely to harm is not shared by the 2023 EFSA opinion or the NHS. Funding and conflicts: Not stated in the abstract. Read: abstract
Wu 2023 Acupuncture and Doxylamine-Pyridoxine for Nausea and Vomiting in Pregnancy: A Randomized, Controlled, 2 x 2 Factorial Trial. Ann Intern Med · PMID 37335994 · DOI	Randomised controlled trial	352 352 women in early pregnancy with moderate to severe nausea and vomiting, 13 hospitals in China	Doxylamine plus pyridoxine (vitamin B6) tablets (a two-ingredient medicine, not B6 alone), with or without acupuncture Tablet 14 days · vs Placebo tablets and sham acupuncture	The doxylamine-pyridoxine group had a larger fall in PUQE score than placebo, and the combination with acupuncture had the largest fall. The authors say the size of the effect was modest, so its clinical importance is uncertain. Babies born small for gestational age were more common with doxylamine-pyridoxine than placebo. Doxylamine-pyridoxine versus placebo: PUQE mean difference -1.0. Small for gestational age: odds ratio 3.8. (PUQE -1.0 (95% CI -1.6 to -0.4); small for gestational age 3.8 (1.0 to 14.1)) Methods, limits and funding Outcomes: Fall in the PUQE nausea and vomiting score at day 15 Limitations: Tests the two-ingredient medicine, so B6 alone is not isolated; effect was modest; the borderline small-baby finding is from one trial; placebo response and natural recovery were not measured. Funding and conflicts: Funded by Chinese national and provincial research programmes; no industry funding named in the abstract. Registration: NCT04401384 Read: abstract
Wyatt 1999 Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ · PMID 10334745 · DOI	Systematic review	940 9 published placebo-controlled trials in women with premenstrual syndrome	Vitamin B6 (pyridoxine) supplements Supplement or food Up to 100 mg a day in the included trials (authors summary) Varied by trial · vs Placebo	Women taking B6 were more likely than women taking placebo to report improvement in overall symptoms, and in depressive symptoms in 4 trials. The authors stress that most of the trials were of low quality. Improvement in overall symptoms: odds ratio 2.32. Depressive symptoms (4 trials, 541 women): odds ratio 1.69. (Overall 2.32 (1.95 to 2.54); depressive symptoms 1.69 (1.39 to 2.06)) Methods, limits and funding Outcomes: Overall premenstrual symptoms; premenstrual depressive symptoms Limitations: Low quality of most trials; published in 1999, so newer trials are not included; abstract gives no funding information. Funding and conflicts: Not stated in the abstract. Read: abstract
s-medlineplus-b6 MedlinePlus Medical Encyclopedia: Vitamin B6 (review date 2025-01-21) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nhs-b6 NHS: Vitamins and minerals, B vitamins and folic acid (vitamin B6 section; page last reviewed 2020-08-03) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-ods-b6 NIH Office of Dietary Supplements: Vitamin B6 fact sheet for health professionals · Source	Reference database n/a			Methods, limits and funding Read: not-read
s-usda-sr-legacy-b6 USDA FoodData Central, SR Legacy (April 2018 release): vitamin B-6 content of common foods · Source	Food database n/a			Methods, limits and funding Read: full-text

What we do not know yet

No trial was read showing that extra B6 helps healthy, well-fed adults.
The US upper intake limit from the NIH could not be read (the page was blocked).
No recent review of B6 alone for pregnancy sickness or premenstrual syndrome was read.
Pyridoxine and PLP pills were not compared.
No source was read on drug interactions beyond one case report, or on supplement contamination.
Pyridoxine-dependent epilepsy, treated with B6 by specialists, was not researched here.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Other 6

●

Blood B6 (pyridoxal 5-phosphate, PLP)

Higher with B6 pills in trials

The active form of B6 measured in blood plasma or red cells; the main marker of B6 status.

High certainty

Results and what it means

Why it was measured

To see whether B6 pills raise a low B6 status.

Statistical vs. clinical meaning

Pills clearly raise blood B6. That shows status improves, not that health outcomes improve.

Safety implication

High blood B6 from pills is the setting in which nerve damage is reported; see the Safety tab.

Study	Result	People	Product
²	Plasma and red-cell PLP and other status markers improved significantly after pyridoxine versus placebo; no number in the abstract.	People with rheumatoid arthritis and low blood PLP	Pyridoxine pills for 30 days
⁷	Plasma PLP weighted mean difference 238 (95% CI 211.58 to 264.42); units not in the abstract.	Healthy men aged 70 to 79 (one trial of 76)	Pyridoxine hydrochloride pills for 12 weeks

^{2 7}

●

Pregnancy sickness score (PUQE)

Lower with doxylamine-pyridoxine (modest) in trials

A questionnaire score of nausea, vomiting and retching in pregnancy; a lower score means less sickness.

Low certainty

Results and what it means

Why it was measured

To see whether doxylamine plus pyridoxine eases pregnancy sickness.

Statistical vs. clinical meaning

The authors say the gain was modest and its clinical importance uncertain.

Safety implication

More babies small for gestational age than with placebo (odds ratio 3.8, 1.0 to 14.1).

Study	Result	People	Product
¹⁵	Mean difference -1.0 (95% CI -1.6 to -0.4) versus placebo at day 15	352 women with moderate to severe sickness in early pregnancy	Doxylamine plus pyridoxine for 14 days

¹⁵

●

Overall premenstrual symptom improvement

More improvement with B6 (low-quality trials) in trials

Whether a woman reported that her premenstrual symptoms improved over placebo.

Low certainty

Results and what it means

Why it was measured

To see whether B6 beats placebo for premenstrual syndrome.

Statistical vs. clinical meaning

Low-quality trials; no recent review of B6 alone was read.

Safety implication

The doses tested were far above current upper limits.

Study	Result	People	Product
¹⁶	Odds ratio 2.32 (95% CI 1.95 to 2.54) for improvement over placebo	9 trials, 940 women with premenstrual syndrome	Vitamin B6 pills

¹⁶

●

Stroke

Slightly lower with B6, B9 and B12 supplements in trials

Whether a person has a stroke during the trial.

Mixed findings

Results and what it means

Why it was measured

To see whether lowering homocysteine with B vitamins prevents stroke.

Statistical vs. clinical meaning

A small difference for the vitamins combined; not specific to B6.

Safety implication

No clear rise in serious adverse events (RR 1.07, 1.00 to 1.14).

Study	Result	People	Product
⁸	RR 0.90 (95% CI 0.82 to 0.99); 4.3% versus 5.1%	10 trials, 44,224 people	Vitamins B6, B9 or B12 alone or combined versus placebo

⁸

●

Lung cancer in men

Higher in men with high 10-year B6 use in trials

New lung cancer diagnoses.

Very low certainty

Results and what it means

Why it was measured

To see whether long-term B6 pills change lung cancer risk.

Statistical vs. clinical meaning

Observational cohort; shows association, not cause.

Safety implication

Possible harm signal in men; none in women.

Study	Result	People	Product
¹	HR 1.82 (95% CI 1.25 to 2.65) for more than 20 mg a day average	77,118 adults, men analysed separately	Single B6 supplements over 10 years (observational)

●

Colorectal cancer risk

Lower with higher B6 intake (association) in trials

New colorectal cancer diagnoses compared with B6 intake or blood level.

Very low certainty

Results and what it means

Why it was measured

To see whether people with more B6 get less colorectal cancer.

Statistical vs. clinical meaning

Observational; could reflect healthier habits.

Safety implication

Does not show that pills lower risk.

Study	Result	People	Product
⁶	Intake OR 0.80 (0.68 to 0.94); blood PLP OR 0.54 (0.35 to 0.84)	28 observational studies	Dietary B6 and blood PLP

⁶

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 4

Too much vitamin B6 from pills can damage nerves. The European Food Safety Authority (2023) calls the link between high B6 intake and peripheral neuropathy well established and bases its upper limit on it. The NHS says 200 mg or more a day can cause loss of feeling in the arms and legs, which usually improves after stopping, but in a few cases, especially after more than a few months, can be permanent. A 2023 review found high B6 levels from supplements may cause a mainly sensory nerve problem that people report improves after stopping. The NHS says the effect of 10 to 200 mg a day is unclear. Regulator opinion, authoritative guidance and systematic review ^{3 18 10 5}
Official upper limits are low, and pills in multivitamins count. EFSA set an upper level of 12 mg a day for adults, including pregnant and breastfeeding women (2023). The NHS tells people not to take more than 10 mg a day in supplements unless a doctor advises it. Some trials of B6 for premenstrual symptoms and anxiety used much higher amounts. A 2023 case report described a 73-year-old man with neuropathy and a very high blood B6 who took only a multivitamin with 6 mg of B6; one case cannot prove cause. These are regulator statements, not advice to take B6. The US upper limit from the NIH could not be read. Regulator opinion, authoritative guidance and case report ^{3 18 12 19}
A possible lung cancer signal in men taking high-dose single B6 pills for years. In a US cohort of 77,118 adults, men with a 10-year average of more than 20 mg a day of B6 from single-vitamin pills had a hazard ratio of 1.82 for lung cancer (95% CI 1.25 to 2.65). It was not seen in women, nor from multivitamins, and was higher in men who smoked. This is an association from one observational study and does not prove cause. Observational cohort ¹
Pregnancy sickness medicine with B6 raised a baby-size signal in one trial. In a 2023 trial of 352 women, babies born small for gestational age were more common with doxylamine plus pyridoxine than with placebo (odds ratio 3.8, 95% CI 1.0 to 14.1). The range barely excludes no difference, the tablets contained two ingredients, and it is one trial. A Cochrane review found little information on harms to mother or baby. Randomised trial (two ingredient medicine) ^{15 9}

Side effects 4

Effect	How often	Severity and recovery	Evidence
Numbness, loss of feeling and trouble coordinating movement (sensory neuropathy) A 2023 case report found a very high blood level and neuropathy in a man taking a multivitamin with 6 mg of B6.	No frequency was found. EFSA bases its upper limit on this effect; the NHS and MedlinePlus name it for large doses.	Usually improves after stopping; the NHS says it can be permanent in a few cases after months of large amounts. Usually reversible on stopping (NHS, 2023 review); can be permanent in some cases (NHS).	Regulator opinion, systematic review and case reports ^{3 18 17 10}
Serious adverse events in trials of B6, folic acid and B12 combinations The review did not separate B6 from the other two vitamins.	Risk ratio 1.07 (95% CI 1.00 to 1.14) versus comparator, 8 trials (35,788 people).	Not described in the abstract. Not stated.	Meta-analysis ⁸
No adverse effects reported in two small trials in healthy older people Short and small; this does not rule out harm from longer use.	None reported in 109 people over 5 and 12 weeks.	Not applicable. Not applicable.	Systematic review ⁷
Possible nerve symptoms worsening in a person on isoniazid who was given pyridoxine See interactions.	One case report.	Symptoms worsened until pyridoxine was stopped. Improved after pyridoxine was stopped (one case).	Case report ¹¹

Liver

MedlinePlus lists liver disease as a cause of low B6. No source read reported liver injury from B6 pills, and a liver-safety database (LiverTox) was not read, so no statement is made. ¹⁷

How often. No frequency was found.

Monitoring. No agency monitoring advice was found.

This is a safety connection. It is not evidence that Vitamin B6 supports liver health.

Medicines and supplements 4

With	Why it matters	Importance	Evidence	What to do
Isoniazid (a tuberculosis medicine) prescription		A 1990 case report described a man whose isoniazid neuropathy worsened on pyridoxine and improved only when it was stopped. The authors urge caution with pyridoxine for preventing or treating isoniazid neuropathy.	Case report Very low certainty ¹¹	Ask the doctor treating the tuberculosis before adding B6.
Levodopa (Parkinson disease medicine) prescription	Not read.	No source with readable findings was read, so no statement is made about what happens.	Not read Not enough evidence	Ask a pharmacist or the prescriber before adding B6 pills.
Other anti-seizure medicines (for example phenytoin or phenobarbital) prescription	Not read.	No source was read, so no statement is made.	Not read Not enough evidence	Ask a pharmacist before adding B6 pills.
Other B vitamins and multivitamins (counting total B6) supplement	Not an interaction; the amounts add up across products.	A 2023 case report found neuropathy and a very high blood B6 in a man taking only a multivitamin with 6 mg of B6, and the VITAL cohort linked single B6 and B12 pills, not multivitamins, to lung cancer in men.	Case report and observational cohort Very low certainty ^{12 1}	Check labels of all products for B6 and ask a pharmacist.

Who should check first 6

Situation	Advice	Evidence
Pregnancy	EFSA includes pregnant women in its 12 mg a day upper level. MedlinePlus gives a Recommended Dietary Allowance of 1.9 mg a day in pregnancy; that is an intake target, not advice to take pills. A trial of a B6-containing sickness medicine found more small-for-gestational-age babies than placebo. Ask a doctor or midwife before any B6 pills.	Regulator opinion, authoritative guidance and randomised trial ^{3 17 15}
Breastfeeding	EFSA includes breastfeeding women in its 12 mg a day upper level, and MedlinePlus gives 2.0 mg a day as the Recommended Dietary Allowance. The NIH LactMed database could not be read. Ask a doctor, midwife or pharmacist before B6 pills.	Regulator opinion and authoritative guidance ^{3 17}
Children	EFSA gave lower upper levels for children: 2.2 to 2.5 mg a day (4 to 11 months), 3.2 to 4.5 mg (1 to 6 years) and 6.1 to 10.7 mg (7 to 17 years). Do not give children B6 pills without advice from a doctor or pharmacist.	Regulator opinion ³
People who already have nerve damage	A 2023 review found B6 within permitted daily doses has not been proven harmful in people who already have neuropathy, but a 2014 review says B6 above 50 mg a day for long periods may be harmful and found inadequate evidence for routine use in nerve disorders. Ask a doctor.	Systematic reviews ^{10 5}
Kidney failure, liver disease or heavy alcohol use	MedlinePlus lists these as situations where low B6 can occur. Ask a doctor about testing instead of guessing.	Authoritative guidance ¹⁷
Men who smoke, taking single B6 or B12 pills for years	A cohort linked this pattern to higher lung cancer risk. It is an association, not proof; ask a doctor.	Observational cohort ¹

Overdose, product quality and regulators

Summary. B6 is a water-soluble vitamin, but large amounts over time are toxic to nerves. EFSA (2023) calls nerve damage the critical effect.

Animal. EFSA identified a lowest-observed-effect level of 50 mg per kg body weight a day from a subchronic study in Beagle dogs (animal data).

High dose or long term signals. NHS: 200 mg or more a day can cause neuropathy, sometimes permanent after months; 10 to 200 mg effect unclear. EFSA: a reference point of 50 mg a day from a case-control study, with an uncertainty factor to give 12.5 mg a day; the final upper level is 12 mg a day for adults.

Overdose response. No source read gave emergency treatment advice for overdose. Stopping the supplement is the step the reviews describe for neuropathy.

Genotoxicity. Not researched.

Contamination and label accuracy of B6 supplements were not researched for this page.

B6 in multivitamins and combination products. B6 is added to many multivitamins and B-complex pills. A case report described neuropathy and a very high blood B6 in a man taking a multivitamin with 6 mg of B6. Cause was not proven. ¹²

Body	Action	Date
European Food Safety Authority (EFSA), Panel on Nutrition, Novel Foods and Food Allergens (European Union)	Set a tolerable upper intake level of 12 mg a day for vitamin B6 for adults, including pregnant and breastfeeding women, based on peripheral neuropathy. For children: 2.2 to 2.5 mg a day (4 to 11 months), 3.2 to 4.5 mg (1 to 6 years), 6.1 to 10.7 mg (7 to 17 years). Says EU populations are unlikely to exceed it except regular users of high-dose supplements. source	2023
NHS (UK National Health Service) (United Kingdom)	Says 200 mg or more of B6 a day can cause loss of feeling in the arms and legs; the effect at 10 to 200 mg is unclear; the Department of Health and Social Care advises not taking more than 10 mg a day in supplements unless a doctor advises it. source	2020-08-03
MedlinePlus (US National Library of Medicine) (United States)	Lists Recommended Dietary Allowances for B6: infants 0 to 6 months 0.1 mg a day (adequate intake), 7 to 12 months 0.3 mg, 1 to 3 years 0.5 mg, 4 to 8 years 0.6 mg, 9 to 13 years 1.0 mg, males 14 to 50 years 1.3 mg, males over 50 1.7 mg, females 14 to 18 years 1.2 mg, females 19 to 50 1.3 mg, females over 50 1.5 mg, pregnancy 1.9 mg, lactation 2.0 mg. Says large doses can cause trouble coordinating movement, numbness and sensory changes. source	2025-01-21

When to get medical help

New numbness, tingling, burning, clumsiness or trouble walking while taking B6 pills (or a multivitamin or B-complex): stop the pills and see a doctor.
Severe vomiting in pregnancy, unable to keep fluids down, dizziness or very dark urine: get medical help the same day.
Someone has swallowed a large amount of B6 or of any supplement by accident, especially a child: call poison control or emergency services.
Confusion, low mood or mouth and tongue sores with kidney, liver or heavy alcohol problems: see a doctor (possible low B6 or other causes).

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What is vitamin B6?

Vitamin B6 is an essential water-soluble vitamin. It helps the body make antibodies and haemoglobin, keep nerves working and break down protein. It comes as pyridoxine, pyridoxal and pyridoxamine.

^{17 18}

What foods have vitamin B6?

Fish such as tuna and salmon, poultry, pork, potatoes, bananas, legumes, nuts, whole grains and fortified cereals. By USDA data, 3 oz of cooked farmed salmon has about 0.55 mg.

^{20 17 18}

What are the signs of low vitamin B6?

MedlinePlus lists confusion, depression, irritability, mouth and tongue sores and nerve damage in the hands and feet. Low B6 is uncommon; it can occur with kidney failure, liver disease or heavy alcohol use. Ask a doctor.

¹⁷

Does vitamin B6 help morning sickness?

The evidence is limited. A 2015 Cochrane review of 41 trials found limited support for B6. A 2023 trial of doxylamine plus pyridoxine found a modest gain and more small-for-gestational-age babies than placebo. Ask a doctor or midwife.

^{9 15}

Does vitamin B6 help premenstrual syndrome?

A 1999 review of 9 trials found women taking B6 were more likely to improve than on placebo, but most trials were of low quality. The trial amounts were far above the current upper limits.

^{16 3}

Does vitamin B6 help with anxiety or memory?

A 2022 trial of 478 young adults found lower self-reported anxiety after a month of high-dose B6. For memory, a 2003 Cochrane review found no benefit in healthy older people.

^{4 7}

Does vitamin B6 protect the heart?

Probably not. A 2017 Cochrane review found B6, folic acid and B12 supplements did not change heart attacks or deaths, with a small stroke difference that is not specific to B6.

⁸

Does vitamin B6 help carpal tunnel syndrome?

A 2007 review calls its effectiveness controversial. No trial results were read. High-dose B6 can itself cause numbness.

^{14 10}

Can vitamin B6 prevent cancer?

Not shown. Observational studies link higher B6 to less bowel cancer, but one cohort linked long-term high-dose single B6 pills to more lung cancer in men. These are associations, not proof.

^{6 1}

Can you take too much vitamin B6?

Yes. Large amounts over time can damage nerves, causing numbness and trouble with coordination. EFSA set an upper level of 12 mg a day for adults and the NHS advises 10 mg a day or less in supplements unless a doctor advises otherwise.

^{3 18 10}

Does vitamin B6 interact with medicines?

A 1990 case report described nerve symptoms worsening when pyridoxine was given with isoniazid, a tuberculosis medicine. Other interactions were not verified here. Ask a pharmacist.

¹¹

Is vitamin B6 safe in pregnancy and for children?

B6 is essential in both. EFSA includes pregnant and breastfeeding women in its 12 mg a day upper level and gave lower limits for children. Ask a doctor, midwife or pharmacist before supplements and do not give children pills without advice.

^{3 17}

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We started from our existing B6 summary, read MedlinePlus and NHS pages, re-checked food values in saved USDA FoodData Central data, and re-read PubMed abstracts for reviews, trials and case reports. Only abstracts were read for studies. The NIH Office of Dietary Supplements page was blocked and is marked unread.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. Trials of B6 products may have manufacturer links not stated in abstracts.

Sources 20

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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.. J Clin Oncol. 2017. PMID 28829668. DOI 10.1200/JCO.2017.72.7735. (abstract)
Chiang EP, Selhub J, Bagley PJ, Dallal G, Roubenoff R. Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis.. Arthritis Res Ther. 2005. PMID 16277693. DOI 10.1186/ar1839. (abstract)
EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA); Turck D, Bohn T, Castenmiller J, de Henauw S, Hirsch-Ernst KI et al. Scientific opinion on the tolerable upper intake level for vitamin B6.. EFSA J. 2023. PMID 37207271. DOI 10.2903/j.efsa.2023.8006. (abstract)
Field DT, Cracknell RO, Eastwood JR, Scarfe P, Williams CM, Zheng Y et al. High-dose Vitamin B6 supplementation reduces anxiety and strengthens visual surround suppression.. Hum Psychopharmacol. 2022. PMID 35851507. DOI 10.1002/hup.2852. (abstract)
Ghavanini AA, Kimpinski K. Revisiting the evidence for neuropathy caused by pyridoxine deficiency and excess.. J Clin Neuromuscul Dis. 2014. PMID 25137514. DOI 10.1097/CND.0000000000000049. (abstract)
Lai J, Guo M, Wang D, Liu K, Hu D, Li J. Association Between Vitamin B6 and the Risk of Colorectal Cancer: A Meta-analysis of Observational Studies.. Nutr Cancer. 2023. PMID 36961108. DOI 10.1080/01635581.2023.2191823. (abstract)
Malouf R, Grimley Evans J. The effect of vitamin B6 on cognition.. Cochrane Database Syst Rev. 2003. PMID 14584010. DOI 10.1002/14651858.CD004393. (abstract)
Marti-Carvajal AJ, Sola I, Lathyris D, Dayer M. Homocysteine-lowering interventions for preventing cardiovascular events.. Cochrane Database Syst Rev. 2017. PMID 28816346. DOI 10.1002/14651858.CD006612.pub5. (abstract)
Matthews A, Haas DM, O'Mathuna DP, Dowswell T. Interventions for nausea and vomiting in early pregnancy.. Cochrane Database Syst Rev. 2015. PMID 26348534. DOI 10.1002/14651858.CD007575.pub4. (abstract)
Muhamad R, Akrivaki A, Papagiannopoulou G, Zavridis P, Zis P. The Role of Vitamin B6 in Peripheral Neuropathy: A Systematic Review.. Nutrients. 2023. PMID 37447150. DOI 10.3390/nu15132823. (abstract)
Nisar M, Watkin SW, Bucknall RC, Agnew RA. Exacerbation of isoniazid induced peripheral neuropathy by pyridoxine.. Thorax. 1990. PMID 2166360. DOI 10.1136/thx.45.5.419. (abstract)
Paluszny A, Qiu S. Vitamin B6 Toxicity Secondary to Daily Multivitamin Use: A Case Report.. Cureus. 2023. PMID 38098895. DOI 10.7759/cureus.48792. (abstract)
Reddy P. Preventing Vitamin B6-Related Neurotoxicity.. Am J Ther. 2022. PMID 36608063. DOI 10.1097/MJT.0000000000001460. (abstract)
Ryan-Harshman M, Aldoori W. Carpal tunnel syndrome and vitamin B6.. Can Fam Physician. 2007. PMID 17872812. (abstract)
Wu XK, Gao JS, Ma HL, Wang Y, Zhang B, Liu ZL et al. Acupuncture and Doxylamine-Pyridoxine for Nausea and Vomiting in Pregnancy: A Randomized, Controlled, 2 x 2 Factorial Trial.. Ann Intern Med. 2023. PMID 37335994. DOI 10.7326/M22-2974. (abstract)
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. PMID 10334745. DOI 10.1136/bmj.318.7195.1375. (abstract)
. MedlinePlus Medical Encyclopedia: Vitamin B6 (review date 2025-01-21). . . (full-text)
. NHS: Vitamins and minerals, B vitamins and folic acid (vitamin B6 section; page last reviewed 2020-08-03). . . (full-text)
. NIH Office of Dietary Supplements: Vitamin B6 fact sheet for health professionals. . . (not-read)
. USDA FoodData Central, SR Legacy (April 2018 release): vitamin B-6 content of common foods. . . (full-text)

Where to buy

Check the label first. Whatever you buy, look for these:

The amount of the active ingredient per serving, not just the front-label claim
A third-party testing mark (USP, NSF or ConsumerLab)
Other ingredients and allergens
Ask a pharmacist about interactions with your medicines

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.