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Ingredient Type: Vitamin

Also Known As: Pyridoxine hydrochloride, Pyridoxine, Pyridoxal-5-Phosphate

Vitamin B-6 is one of eight B Vitamins and an essential nutrient for all animals obtained only through the diet. Natural sources include cereal grains, legumes, vegetables (carrots, spinach, peas, and potatoes), milk, cheese, eggs, fish, liver, meat, and flour. It is involved in the process of making serotonin and norepinephrine, which are chemicals that transmit signals in the brain.

Vitamin B-6 is also involved in the formation of myelin, a protein layer that forms around nerve cells. Deficiency in adults may cause health problems affecting the nerves, skin, mucous membranes, and circulatory system.

Vitamin B6 is coenzyme.  Enzymes are substances that speed up reactions. They do this to help the body perform a task, which can be anything from digesting food to keeping the liver functioning properly. A coenzyme is a molecule that works with the enzyme to aid it in carrying out its job. Without the coenzyme, the enzyme would be useless. As a coenzyme, vitamin B6 assists in a variety of tasks, including:

  • The creation of heme, the iron-containing component of red blood cells;
  • Making the hormone serotonin (the “feel good” hormone);
  • Processing carbohydrates for energy;
  • Keeping the nervous system working smoothly

Vitamin B6 is a member of the vitamin B family. It is present in many foods including cereal grains, legumes, vegetables, liver, meat, and eggs. In the body, vitamin B6 is required for amino acid metabolism. It is also involved in carbohydrate and lipid metabolism.

P5P is an active form of vitamin B6 that your body can easily utilize, often referred to as P5P for short. It is the active form of vitamin B6. In foods or most supplements, vitamin B6 is found in one of three forms: pyridoxine hydrochloride, pyridoxal, or pyridoxamine. Inside the body, these forms of B6 must be converted by the liver to the active form the body needs – P5P.  Low rates of conversion from the inactive to the active form of vitamin B6 have been reported, especially in people with impaired liver function, celiac’s disease, older adults, and in children with autism. By consuming vitamin B6 in the active P5P form, conversion is no longer necessary, and the full benefits are available immediately after absorption.

Vitamin B6 was first described by Paul Gyorgy in 1934. He determined that dermatitis acrodynia, a skin disease that occurs in rats fed a diet devoid of vitamin B complex but still containing vitamin B1 and vitamin B2, could be treated by giving them a particular substance that Gyorgy called vitamin B6. By 1938, vitamin B6 was isolated, and it was first synthesized shortly thereafter. Initially, pure vitamin B6 was referred to as pyridoxine. In the mid-1950s it was determined that vitamin B6 actually occurs naturally in several forms: pyridoxine, pyridoxal, pyridoxamine, and the phosphate derivatives of these forms (1).


Vitamin B-6 is used in health supplements today to help with brain and nervous system function.

One commonly used purpose is to increase attention span in attention deficit-hyperactivity disorder (ADHD).


Age-related cognitive impairment: One clinical trial shows that taking a combination of B vitamins for 24 months reduces cerebral atrophy in the gray matter regions associated with Alzheimer’s disease, by up to seven-fold compared with placebo in elderly people with memory complaints. However, this protection does not occur in patients with the lowest average blood levels of homocysteine (17). Furthermore, other clinical research shows that taking vitamin B6 (pyridoxine) in combination with folic acid and vitamin B12 (cyanocobalamin) does not improve cognitive function in elderly patients (18).

Attention deficit-hyperactivity disorder (ADHD): Preliminary clinical research suggests that taking vitamin B6 (pyridoxine) orally, alone or in combination with high doses of other B vitamins, might help ADHD (19). However, research using megadose vitamin B6 (pyridoxine) in combination with other megadose vitamins seems to show no effect on ADHD symptoms (20).


Considered safe when used orally and appropriately it is deemed safe. Injectable vitamin B6 (pyridoxine) is an FDA-approved prescription product.

Orally or by injection, vitamin B6 (pyridoxine) can cause nausea, vomiting, abdominal pain, heartburn, loss of appetite, headache, paresthesia, somnolence, and decreased serum folic acid concentrations. It has also been linked to reports of skin and other allergic reactions, breast soreness or enlargement, and photosensitivity (13) Vitamin B6 (pyridoxine) can cause sensory neuropathy, which is related to daily dose and duration of intake. Doses exceeding 1000 mg daily or total doses of 1000 grams or more pose the most risk, although neuropathy can occur with lower daily or total doses as well (14). High-dose vitamin B6 (80 mg/day as pyridoxine) and vitamin B12 (20 micrograms/day) may result in intense erythema with nodules, papules, and pustules, possibly requiring treatment with systemic corticosteroids and topical therapy (16). There is some preliminary concern that long-term dietary vitamin B6 intake in small amounts ranging from 3.56-6.59 mg daily can increase the risk of developing ulcerative colitis (17).

Moderate interactions with prescriptions: Amiodarone, antihypertensive, levodopa, phenobarbital, phenytoin (22)

Interactions with Herbs and supplements: Theoretically may increase the risk of hypotension. examples: andrographis, casein peptides, cat’s claw, coenzyme Q10, fish oil, L-arginine, lycium, stinging nettle, theanine and others. (21)


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  17. Douaud G, Refsum H, de Jager CA, et al. Preventing Alzheimer’s disease-related gray matter atrophy by B-vitamin treatment. Proc Natl Acad Sci U S A 2013;110(23):9523-8.
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See the National Institutes of Health Office of Dietary Supplements entry for vitamin B6, the MedlinePlus entry for pyridoxine, the RXList entry for pyridoxine, the Michigan Medicine Health Library entry for vitamin B6, or the entry for vitamin B6 for more information.