Vitamin B6

vitamin

Best with a mealTake with food

What is it

Vitamin B6 is a water-soluble vitamin involved in more than 100 enzyme reactions, mostly related to protein metabolism, neurotransmitter synthesis, and red blood cell formation. It exists in several related forms.

How it works

All dietary forms of B6 are converted in the body to pyridoxal 5-phosphate (PLP), the active coenzyme form. PLP supports amino acid metabolism, gluconeogenesis, hemoglobin synthesis, and the production of neurotransmitters including serotonin, dopamine, and GABA. It is also needed for the conversion of tryptophan to niacin. B6 is absorbed in the small intestine. The liver phosphorylates and dephosphorylates B6 forms as they cycle between blood and tissues. Most of the body's B6 is stored in muscle bound to glycogen phosphorylase.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Treatment of deficiency

Grade A

Strong evidence

Supplementation corrects deficiency, which can cause anemia, dermatitis, and neurological symptoms. Deficiency is relatively uncommon in well-nourished populations.

Pregnancy-related nausea

Grade B

Good evidence

B6 (often 10 to 25 mg three times daily, sometimes combined with doxylamine) reduces nausea in early pregnancy. It is widely recommended and considered safe.

Lowering homocysteine

Grade B

Good evidence

B6 alongside folate and B12 lowers homocysteine. Whether this prevents cardiovascular events is uncertain — large trials have been mostly negative.

Premenstrual symptoms

Grade C

Moderate evidence

Some trials suggest modest benefit for PMS symptoms, but evidence is mixed and high-dose use risks neuropathy. Doses above 100 mg per day are not recommended for this purpose.

Carpal tunnel syndrome

Grade D

Mixed evidence

Older studies suggested benefit but better-designed trials have not confirmed it. Not a first-line treatment.

2 commercial forms

Pyridoxine HCl

standard, inexpensive, converted in the liver

The most common supplement form. Highly bioavailable and converted to active PLP in the body.

Pyridoxal 5-phosphate (P5P)

active form, may be preferred for some

The biologically active coenzyme form. Marketed as superior, but no consistent evidence it works better than pyridoxine in healthy people. May be preferable in liver dysfunction.

Dosage

The RDA for adults is 1.3 mg per day, rising to 1.7 mg for men over 50 and 1.5 mg for women over 50. Pregnant and breastfeeding women need 1.9 to 2.0 mg. Supplements commonly provide 25 to 100 mg. The tolerable upper limit is 100 mg per day for adults — exceeding this long-term risks nerve damage.

When and how to take it

Vitamin B6 absorbs well with or without food, though taking it with meals can reduce occasional nausea. As a water-soluble vitamin it is not stored long-term, so daily dosing is appropriate. Some people take B6 in the evening for its role in serotonin and melatonin synthesis, but no strong evidence supports a specific time of day.

Food sources

Food	Amount	%DV
Chickpeas (canned), 1 cup	1.1 mg	65%
Beef liver, 3 oz cooked	0.9 mg	53%
Tuna (yellowfin), 3 oz cooked	0.9 mg	53%
Salmon (sockeye), 3 oz cooked	0.6 mg	35%
Chicken breast, 3 oz cooked	0.5 mg	29%
Banana, 1 medium	0.4 mg	24%
Potato (baked, with skin)	0.4 mg	24%
Fortified breakfast cereal	0.5 mg per serving	29%

Safety

Vitamin B6 at typical supplemental doses is safe. Long-term intake above 100 mg per day — and especially above 200 mg per day — can cause sensory peripheral neuropathy: numbness, tingling, and difficulty walking. The damage is usually reversible if the supplement is stopped early, but symptoms can persist if exposure is prolonged. Food sources do not cause toxicity. Many cases of B6-induced neuropathy come from people taking high-dose B-complex supplements not realizing the cumulative dose.

Who should be cautious

Anyone taking long-term high-dose B6 should be alert for early signs of nerve symptoms. People on isoniazid are typically given supplemental B6 to prevent drug-induced deficiency. Pregnant women sometimes use B6 (10 to 25 mg) for nausea — this is generally considered safe and is part of some prescription anti-nausea combinations.

Interactions

Several drugs can lower B6 levels or interfere with its function, including isoniazid (tuberculosis treatment), hydralazine, penicillamine, and some seizure medications. Levodopa for Parkinson's disease can be inactivated by B6 if not combined with carbidopa. Oral contraceptives modestly lower B6 status.

Frequently asked questions

How much vitamin B6 is too much?⌄

Long-term intake above 100 mg per day, and especially above 200 mg, risks sensory nerve damage. The upper limit is 100 mg per day for adults.

Is P5P better than pyridoxine?⌄

For most healthy people, no consistent advantage has been shown. People with significant liver dysfunction may benefit from the pre-activated P5P form.

Does vitamin B6 help with morning sickness?⌄

Yes. B6 (around 10 to 25 mg, often combined with doxylamine) is widely used for pregnancy nausea and is considered safe.

What are signs of B6 deficiency?⌄

Symptoms include skin inflammation, cracked lips, sore tongue, depression, confusion, and weakened immunity. Deficiency is uncommon in well-fed populations.

Can B6 cause numbness or tingling?⌄

Yes, at high doses (typically above 200 mg per day long-term). Stopping the supplement usually reverses symptoms over weeks to months.

Track Vitamin B6 with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.