Vitamin B6
Runs the reactions behind mood and metabolism. Also the B vitamin most likely to cause harm at high doses.
Vitamin B6 (pyridoxine) is needed for over 100 enzyme reactions, including amino acid metabolism, red blood cell formation, and neurotransmitter production. Standard pyridoxine HCl needs to be converted by the liver into its active coenzyme form, PLP, while P5P supplements provide that active form directly. B6 is also one of the few water-soluble vitamins with a real upper limit: European regulators revised the recommended ceiling downward in 2023 after evidence that nerve damage can develop at lower doses than previously assumed, so high-dose B6 supplements, common in energy and stress formulas, deserve more caution than most people expect.
Reference values
Daily reference values from official nutrition authorities. These are population reference figures, not personal recommendations.
| RDA | Upper limit | Source |
|---|---|---|
| 1.4 mg | 12 mg | UK SACN DRVs (1991) 1.4mg/day; EFSA NDA Panel UL revised to 12mg/day (2023 revision, EFSA Journal 2023;21(5):8006 — peripheral neuropathy risk at lower doses than the prior 25mg/2006 UL assumed) |
| 1.4 mg | 12 mg | UK SACN DRVs (1991) 1.4mg/day; EFSA NDA Panel UL revised to 12mg/day (2023 revision, EFSA Journal 2023;21(5):8006 — peripheral neuropathy risk at lower doses than the prior 25mg/2006 UL assumed) |
Forms and bioavailability
Not all forms are absorbed equally. The form on your supplement label affects how much your body can actually use.
| Form | Absorption | With food | Timing | Evidence |
|---|---|---|---|---|
| Pyridoxine HCl | Typical | With food | Morning | Strong |
| Pyridoxal-5-Phosphate (P5P) | Higher | With food | Morning | Likely |
How it pairs with other supplements
Works well with
Magnesium is a cofactor for pyridoxal kinase, required to convert pyridoxine to its active coenzyme form PLP. Adequate magnesium status supports full B6 activation.
Folate and B6 are part of the three-way homocysteine-lowering triad (folate + B12 + B6). Folate supports remethylation, B6 supports transsulfuration. Combined supplementation provides broader homocysteine pathway support than either alone.
B6 and B12 work together in homocysteine metabolism: B12 enables remethylation (methionine synthase pathway), B6 enables transsulfuration (cystathionine beta-synthase pathway). Combined supplementation shows additive homocysteine reduction.
Stack Almanac adds up your B6 from every supplement you log, including B-complex and stress formulas, and flags your total against the upper limit before high-dose B6 becomes a problem.
Track your Vitamin B6 in Stack Almanac
Last reviewed: 2026-07-08. Reference values are adult-general RDAs from UK. Individual needs may vary. This page is for informational purposes only and is not a substitute for professional medical advice.