Vitamin B6

Supplements · Vitamins · Supplement, Typed Supps

Involved in over a hundred different reactions in your body.

Stage by stage

Intake (Tablet): Absorbed efficiently in the small intestine.
Small intestine (Absorbed): Absorbed efficiently in the small intestine.
Liver (Converted to active form): Converted by the liver into its active form.
Cells (Neurotransmitter cofactor): Used as a cofactor in neurotransmitter synthesis and amino acid metabolism.

What the evidence supports

Correcting a documented deficiency — strong evidence. Clear, though isolated B6 deficiency is uncommon outside specific medications and alcohol dependence.
Reducing nausea in pregnancy — moderate evidence. Well enough supported that B6, often with doxylamine, is a standard first-line option — under medical guidance.
Relieving premenstrual symptoms — limited evidence. Some supportive trials, mostly older and small. Doses used often approach the range where nerve damage becomes a risk.
Improving mood or energy in people who are not deficient — insufficient evidence. A staple of energy formulas without evidence behind that use.

Typical dose

Around 1.3 to 2 mg daily is all most people need, and food supplies it. Supplements routinely contain 10 to 100 mg, which is not a correction of any dietary shortfall. The doses used for nausea in pregnancy are much higher than the RDA and belong under medical guidance.

Upper limit: 100 mg daily in the US, covering food and supplements together, and set specifically to protect against nerve damage. EFSA is far more cautious at 12 mg daily for adults. Chronic gram-level intakes cause severe progressive sensory neuropathy, and cases have been reported below 500 mg daily.

Timing

With food, standard dosing.

Time to effect

Weeks: Levels normalize with regular intake.

Medication interactions

Levodopa (without carbidopa): B6 speeds its breakdown outside the brain and can substantially reduce its effect. (high)
Phenytoin and phenobarbital: B6 can lower blood levels of these anti-seizure medicines. (high)
Isoniazid, penicillamine, cycloserine: These deplete B6 — a reason it is often prescribed alongside them. (moderate)

Common myth

“More B6 means more energy.” In reality: Very high long-term doses have been linked to nerve damage — one of the few water-soluble vitamins where excess is a real concern.

Food sources

Quail — Protein
Banana — Fruit
Bream — Protein
Camel — Protein
Chestnut — Protein
Chicken — Protein