Pyridoxal 5'-Phosphate (P5P)
Also known as: P5P, PLP, pyridoxal phosphate, active B6, pyridoxal-5-phosphate monohydrate, coenzyme B6
Pyridoxal 5'-phosphate is the active coenzyme form of vitamin B6 and the form measured in blood to assess B6 status. As a supplement it is positioned as an already-activated B6 that does not depend on liver conversion, which is the selling point in premium B-complex, methylation, and nerve-support products. NIH ODS notes some supplements contain PLP and that absorption does not differ substantially among B6 forms; it is dephosphorylated in the gut and re-phosphorylated inside cells. The 100 mg vitamin B6 UL applies.
Research summary
Coenzyme for transaminases, amino acid decarboxylases (serotonin, GABA, dopamine), and glycogen phosphorylase; dephosphorylated before absorption and regenerated intracellularly.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 1.3 mg | 1.7–50 mg | 100 mg | 100 mg |
NIH ODS — UL is 100 mg/day of vitamin B6 for adults 19+ from all sources; applied to P5P
Doses are mg pyridoxal 5'-phosphate monohydrate as labeled. On a molar basis 1 mg pyridoxine HCl (MW 205.6) corresponds to about 1.29 mg P5P monohydrate (MW 265.2), so a 50 mg P5P dose is somewhat less B6 than 50 mg pyridoxine HCl; declare the vitamin B6 amount on the label per the supplier's equivalence. Same RDA (1.3 to 1.7 mg) and DV (1.7 mg) as pyridoxine. A 6-month randomized trial combined P5P with methylfolate and methylcobalamin in adults with elevated homocysteine; dose_max_studied is capped at the UL.
Standardization: ≥98% pyridoxal 5'-phosphate monohydrate
Source material: synthetic
Forms of Vitamin B6
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Pyridoxal 5'-Phosphate (P5P) | 1.7–50 mg | — | Capsule, Tablet, Powder, Liquid | mid |
| Vitamin B6 (Pyridoxine HCl) | 1.7–50 mg | — | Capsule, Tablet, Powder, Gummy, Liquid | low |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Pale yellow, light- and heat-sensitive; less stable than pyridoxine HCl in gummies and hot-process formats.
Formulation notes
Typically combined with L-5-MTHF and methylcobalamin in methylation formulas. Same drug interactions as pyridoxine at high doses.
- Has an upper limit
Sources
- Vitamin B6 — Health Professional Fact SheetNIH ODS
- Effect of Methylfolate, Pyridoxal-5'-Phosphate, and Methylcobalamin (SolowaysTM) Supplementation on Homocysteine and Low-Density Lipoprotein Cholesterol Levels in Patients with Methylenetetrahydrofolate Reductase, Methionine Synthase, and Methionine Synthase Reductase Polymorphisms: A Randomized Controlled Trial. (Pokushalov E, 2024)PubMed
Related ingredients
Vitamin B12 (Cyanocobalamin)
VitaminCyanocobalamin is the synthetic, highly stable form of vitamin B12 used in most supplements and fortified foods.
Typical: 100–1,000 mcg
Vitamin B12 (Methylcobalamin)
VitaminMethylcobalamin is one of the two coenzyme forms of vitamin B12 that the body uses directly, in this case for the methionine synthase reaction that recycles homocysteine and supports methylation.
Typical: 100–1,000 mcg
Vitamin B6 (Pyridoxine HCl)
VitaminPyridoxine hydrochloride is the standard, inexpensive, and highly stable form of vitamin B6 used in nearly all multivitamins and B-complex products.
Typical: 1.7–50 mg
Vitamin D3 (Cholecalciferol)
VitaminThe form of vitamin D the body makes from sunlight and the most effective supplemental form for raising blood levels.
Typical: 1,000–2,000 IU
Folic Acid
VitaminFolic acid is the fully oxidized, synthetic form of folate used in food fortification and most supplements.
Typical: 400–800 mcg