Pyridoxal-5-Phosphate B6 P5P Capsules

Each capsule provides 34 mg of vitamin B6 as pyridoxal 5-phosphate, which is 2429% of the nutrient reference value. Take 1 capsule per day with food, as the label directs, for the period a practitioner has advised. Pots hold 60 or 120 capsules. The capsule contains pyridoxal 5-phosphate with cellulose as the carrier in a vegetarian cellulose shell, and it is vegan and free from gluten, dairy and nuts.

Sources: NIH Office of Dietary Supplements; product label.

P5P is the short name for pyridoxal 5-phosphate, the active form of vitamin B6, the form that enzymes in the body use directly. Vitamin B6 is a family name for six related compounds: pyridoxine, pyridoxal and pyridoxamine, and the phosphate forms of each. Pyridoxal 5-phosphate is the coenzyme for more than 100 enzyme reactions, most of them to do with protein, and doctors measure vitamin B6 status by the level of it in the blood, which is why the name appears on test results. The vitamin dissolves in water, so the body does not store it and needs a supply every day.

Sources: NIH Office of Dietary Supplements; Food Standards Scotland; MeSH, US National Library of Medicine.

P5P capsules give vitamin B6 already in its active form. Pyridoxine, the form in most supplements and fortified foods, is converted into pyridoxal 5-phosphate in the liver first. Absorption from supplements is similar across the forms, and the gut strips the phosphate from P5P before absorption and puts it back inside the body, so the case for P5P rests on form and safety rather than absorption. In a 2017 laboratory study on human nerve cells, pyridoxine harmed the cells and blocked the enzymes that depend on pyridoxal 5-phosphate, while P5P did not; that finding comes from cells in a dish and has not been tested in people. These capsules are a P5P supplement only, with no pyridoxine hydrochloride.

Sources: NIH Office of Dietary Supplements; peer-reviewed study (Vrolijk and colleagues, Toxicology in Vitro, 2017).

P5P supplies vitamin B6, which the body uses in the handling of protein and carbohydrate from food. It also builds haemoglobin, which carries oxygen in the blood, and makes the nerve-signalling chemicals serotonin and noradrenaline. Vitamin B6 also keeps blood levels of homocysteine, an amino acid, in the normal range, and it helps the body produce lymphocytes for the immune system. Research on supplements above normal intakes is mixed: a review of nine trials in about a thousand women found vitamin B6 eased premenstrual symptoms more than placebo, but most of the trials were small and weak, and trials in 6837 heart patients found 40 mg a day lowered homocysteine without reducing heart attacks.

Sources: NIH Office of Dietary Supplements; Food Standards Scotland.

P5P capsules at 34 mg a day are for the period a practitioner or GP has advised, not for open-ended daily use. Adults need about 1.4 mg of vitamin B6 a day for men and 1.2 mg for women, and food provides that for most people. UK advice is not to take more than 10 mg a day from supplements unless a doctor advises it, the European upper level set in 2023 is 12 mg a day, and the American upper level is 100 mg a day; this capsule sits above the first two. Doses between 10 and 200 mg for short periods might not cause harm, but no one knows how long they can be taken safely. New tingling or numbness in the hands or feet means stop and speak to a GP.

Sources: Food Standards Scotland; NIH Office of Dietary Supplements; EFSA.

P5P capsules give a fixed 34 mg a day in one step, while the liquid gives 848 mcg per drop and builds up. A capsule suits a practitioner-set course; the liquid suits everyone else, because it keeps the intake near the long-term UK guidance figure.

Sources: NIH Office of Dietary Supplements; product label.

P5P capsules are for people who want an active B6 supplement at a higher amount their practitioner or GP has set for a defined time. That includes people with a tested low level, and anyone who wants the active form rather than pyridoxine at this strength. Food alone meets the requirement for most people, so anyone unsure whether they need extra vitamin B6 should ask a GP for a blood test rather than self-treating.

Sources: Food Standards Scotland; NIH Office of Dietary Supplements.

P5P is most often taken with magnesium or with the other B vitamins, and both pairings have been studied. In a trial of 264 stressed adults, 300 mg of magnesium with 30 mg of vitamin B6 for eight weeks worked no better than magnesium alone overall. Vitamin B6 taken with folic acid and vitamin B12 lowers homocysteine more than any one of them alone. Prescription drugs are the interactions that matter: some antiepileptic drugs, including valproate, carbamazepine and phenytoin, lower blood levels of vitamin B6, and high-dose pyridoxine lowers blood levels of phenytoin and phenobarbital in return. Anyone on regular prescriptions should ask a pharmacist first.

Sources: NIH Office of Dietary Supplements; peer-reviewed trial (Pouteau and colleagues, PLOS ONE, 2018).

P5P at the amounts in food and low-dose supplements has no reported side effects. The risk with vitamin B6 comes from high doses over long periods: more than 200 mg a day, or lower amounts for a long time, can damage the sensory nerves and cause loss of feeling, tingling or pain in the hands and feet. Symptoms usually fade once the supplement is stopped, but in some people who took large amounts for months they did not reverse. That is why these capsules are a short course on advice. Anyone pregnant or breastfeeding, or taking prescribed tablets, should speak to a GP or pharmacist first.

Sources: NIH Office of Dietary Supplements; Food Standards Scotland.