← The FormularyLong gameVitamin B6
Also known as Pyridoxine / P5PSmall number. Hard ceiling.
B6 is the water-soluble vitamin that breaks the 'you just pee out the excess' rule, and this deserves plain speech. Sustained high intakes cause peripheral neuropathy — numbness, tingling and pain in the hands and feet — and while it usually reverses when you stop, it does not always. The regulators disagree about where the line is: the US sets the upper limit at 100 mg a day, Europe revised theirs down to 12 mg. That gap is real scientific uncertainty, not a rounding error. Our amounts sit inside it: INTAKE has 26 mg, PROSTATE 13.8 mg, NERVE 2.5 mg, and the B-complex products (RESET, SHIFT) carry a trace — about a third of a day's requirement. The instruction that follows is simple and worth more than the debate: pick one B6 source and do not stack. If you take INTAKE and PROSTATE together, that is roughly 40 mg a day, and you should know it.
A water-soluble essential vitamin, active in the body as pyridoxal-5-phosphate (P5P) — the form some formulas use directly.
P5P is a coenzyme: it clips onto enzymes and lets them do chemistry they cannot do alone. Amino-acid metabolism, haemoglobin synthesis and the conversion of tryptophan to serotonin all run through it, which is why it turns up in formulas about mood, sleep, energy and hormones alike.
Runs more than a hundred enzyme reactions, most of them in protein metabolism, and is required to build the neurotransmitters serotonin, dopamine and GABA.
Nearly everyone gets enough from food — poultry, fish, potatoes, chickpeas, bananas. Supplemental B6 earns its place inside a formula with a specific job, not as a standing addition.
Daily with food. P5P is the pre-activated form and is what INTAKE uses; ordinary pyridoxine converts perfectly well in most people.
Nothing noticeable if your intake was already adequate, which it probably was. Correcting a genuine deficiency is a different matter, and a blood test question.
Grade A as an essential nutrient. The neuropathy risk is documented at sustained intakes above 100 mg/day, with case reports at lower amounts; EFSA's 2023 review set a tolerable upper level of 12 mg/day, while the US NIH figure remains 100 mg/day. Australia's regulator now requires warning labels above 10 mg/day. Read your total intake across every product you take, not the number on one panel.
Read the labelDo not take two B6 sources at once. Sustained high intakes can cause peripheral neuropathy — numbness and tingling in hands and feet. The US upper limit is 100 mg/day; European regulators set theirs at 12 mg. Speak to a doctor first if you take levodopa or phenytoin.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.