Background Information
Vitamin B-6 is required for energy and amino acid metabolism, and several other essential functions. The dietary requirement for this vitamin increases with higher amounts of dietary protein, which presents greater amounts of amino acids that need to be metabolized.

Dietary vitamin B-6 activity can be provided by any one of several closely related substances: pyridoxol, pyridoxal, pyridoxamine and their phosphorylated forms. As nutrient additives in conventional foods or dietary supplements, pyridoxol is often salted with hydrochloric acid to form pyridoxine (vitamin B-6) hydrochloride.

 Effects on Health
The Dietary Reference Intake for vitamin B6 is 1.3 mg/d. Higher doses of vitamin B-6 have been used for several purposes, including premenstrual syndrome (PMS), diabetic neuropathy, carpal tunnel syndrome, and as an ergogenic aid. The effectiveness varies across these uses, and may also depend on biological individuality. Most of the evidence for effectiveness for premenstrual tension is anecdotal. The evidence for effectiveness in diabetic neuropathy, carpal tunnel syndrome, and ergogenesis is inconsistent and unclear.

Recent evidence suggests that vitamin B-6 intakes of at least several times the RDA may reduce the risk of heart disease and help folic acid and vitamin B-12 maintain low plasma homocysteine (a risk factor for heart disease).

Vitamin B-6 occurs in many foods and is a common and appropriate component of multivitamin and B-complex supplement products. Single-nutrient supplements of vitamin B-6 are available in potencies of 200 mg or more. Total intake should be considered.

 Effects on Performance
Because vitamin B6 plays a role in energy production, it has been suggested that the requirement for this vitamin is increased during exercise. However, there are no well-documented studies showing that exercise increases the loss of vitamin B6 from the body at a rate greater than can be easily replaced by eating foods that are good sources of this vitamin. Additionally, research has shown that there is no effect of vitamin B-6 supplementation on physical endurance, but the effect may depend on duration of exercise and the amounts and proportions of macronutrients in the diet.