Vitamins · 4 min read ·

Vitamin B6: beware of high doses

The body needs vitamin B6 to convert amino acids and make nerve messengers. A deficiency is rare — a more common problem is high-dose supplements that damage nerves.

B6

In a nutshell

1What it does and how much you need

Vitamin B6 is the collective name for six related substances — pyridoxine, pyridoxal, pyridoxamine and their phosphates. Its active forms help enzymes convert amino acids and make haemoglobin and nerve messengers. A deficiency is rare and shows as anaemia and nerve problems.1

EFSA recommendation 1.7 / 1.6 mg EFSA recommends 1.7 mg of vitamin B6 a day for men and 1.6 mg for women, 1.8 mg in pregnancy and 1.7 mg when breastfeeding. According to EFSA, the requirement does not depend on the amount of protein in the diet.1

2Where to find it

Data 1.7 mg A hundred grams of pistachios contain 1.7 mg of vitamin B6, sunflower seeds and wheat germ 1.3 mg, beef liver 1.1 mg and chicken or turkey breast about 0.8 mg.3

3Forms and absorption

EFSA recommendation 95% / 75% Pyridoxine, pyridoxal and pyridoxamine are absorbed similarly. Pyridoxine glucoside from some plants is absorbed about half as well, so the uptake from a mixed diet is around 75%; from supplements about 95%.1

In the EU, supplements may contain vitamin B6 as pyridoxine hydrochloride, pyridoxine 5′-phosphate or pyridoxal 5′-phosphate (P5P).4 The body can convert all forms to the active pyridoxal 5′-phosphate.1

Weak evidence — a cell experiment pyridoxine In a laboratory experiment on nerve cells, only pyridoxine — not the other forms — damaged the cells at high concentrations, and it also blocked active P5P. The authors conclude that pyridoxine is behind the nerve damage after high doses; this has not been confirmed in people, however.5

4When it harms

EFSA recommendation 12 mg In 2023 EFSA set the upper level for adults, including pregnant and breastfeeding women, at 12 mg a day. Too much vitamin B6 damages the peripheral nerves, which can show as tingling, numbness or pain in the hands and feet. According to EFSA, the limit is exceeded in the EU mainly by people who regularly take high-dose supplements.2

The starting point for the limit was 50 mg a day from a study in which nerve damage occurred; EFSA divided it by four because of uncertainties. According to the authors of the laboratory study, more than 50 cases of nerve damage after vitamin B6 supplements were reported since 2014 alone.2,5

Weak evidence 9 studies A review of 9 studies with 940 women: vitamin B6 at doses up to 100 mg a day eased premenstrual symptoms. But most of the studies were of low quality and the doses far exceed today’s upper level.6
Weak evidence — Cochrane 41 studies A Cochrane review of treatments for nausea in early pregnancy (41 studies) found only limited evidence that vitamin B6 eases mild nausea.7

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. EFSA NDA Panel (2016). Dietary reference values for vitamin B6. EFSA Journal 14:4485. doi.org/10.2903/j.efsa.2016.4485
  2. EFSA NDA Panel (2023). Scientific opinion on the tolerable upper intake level for vitamin B6. EFSA Journal 21:e08006. doi.org/10.2903/j.efsa.2023.8006
  3. USDA ARS (2018). FoodData Central — SR Legacy, vitamin B6 per 100 g: pistachios 1.7 mg (FDC 170184), sunflower seeds 1.3 mg (FDC 170562), wheat germ 1.3 mg (FDC 168892), beef liver, raw 1.1 mg (FDC 169451), turkey breast, raw 0.8 mg (FDC 171098), chicken breast, skinless, raw 0.8 mg (FDC 171077). fdc.nal.usda.gov
  4. Directive 2002/46/EC on food supplements, Annex II — forms of vitamins and minerals permitted in supplements (consolidated version 26 Nov 2025). eur-lex.europa.eu
  5. Vrolijk M. F. et al. (2017). The vitamin B6 paradox: supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function. Toxicol In Vitro 44:206–212. doi.org/10.1016/j.tiv.2017.07.009
  6. Wyatt K. M. et al. (1999). Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ 318:1375–1381. doi.org/10.1136/bmj.318.7195.1375
  7. Matthews A. et al. (2015). Interventions for nausea and vomiting in early pregnancy. Cochrane Database Syst Rev CD007575. doi.org/10.1002/14651858.CD007575.pub4

This is general information and does not replace a doctor. Food supplements are not medicines; buy them from trusted sellers and talk to a doctor if you are ill or take medicines.