Vitamin B6

What It Is

Vitamin B6—also known as pyridoxine—is a water-soluble B vitamin found in foods and supplements. In the body, B6 is converted into its active form, pyridoxal-5-phosphate (PLP), which is required for hundreds of cellular reactions. Because it is water-soluble, the body does not store much of it; most excess is excreted in urine, so steady intake is needed.

Common dietary sources include poultry, fish, potatoes, bananas, chickpeas, nuts, and fortified cereals. It is also available as a standalone supplement and in B-complex formulas or multivitamins.

How It Works

Vitamin B6 functions mainly as a coenzyme—meaning it helps enzymes operate—in metabolic pathways that process protein, carbohydrates, and fats. One of its most important roles is in amino-acid metabolism: the body uses B6 to synthesize and break down proteins, create neurotransmitters such as serotonin, dopamine, and GABA, and make hemoglobin, the oxygen-carrying protein in red blood cells.

B6 also participates in the regulation of homocysteine, an amino-acid byproduct that, when elevated, is linked to cardiovascular risk. Through its coenzyme form PLP, B6 assists in converting homocysteine back to methionine or onward to cysteine, helping prevent buildup that could damage vascular tissue.

Why It’s Important

Because of its involvement in neurotransmitter synthesis and red-blood-cell formation, vitamin B6 is directly tied to nervous-system function, mood regulation, and oxygen delivery in the body. Deficiency can manifest as irritability, depression, confusion, anemia, cracked or inflamed skin, and weakened immunity.

In pregnancy, adequate B6 supports fetal brain development and is often used to help manage nausea in early pregnancy under medical direction. In older adults, sufficient B6 may help maintain cognitive function, support immune response, and reduce elevated homocysteine when combined with folate and B12.

Considerations

While B6 is essential, both deficiency and excess can cause problems. Since it is widely available in food and commonly included in multivitamins, deficiency in healthy people eating a varied diet is uncommon, but can occur in malabsorption conditions, alcoholism, kidney disease, or with certain medications such as isoniazid or hydralazine.

High supplemental doses taken chronically—not from food—can cause sensory neuropathy, leading to numbness, tingling, or burning in the hands and feet. This toxicity has been reported with prolonged intake well above the upper limit. For most people, the safest approach is to meet needs primarily through food or standard-dose supplements, and to reserve higher doses for specific medical indications with supervision.

Women who are pregnant, people on interacting medications, or those with chronic disease should discuss dosing with a clinician rather than self-titrate high doses. Because B vitamins interact in homocysteine metabolism, B6 supplementation is sometimes paired with folate and B12; in such cases, the balance of these nutrients matters more than any one in isolation.