Vitamin B6
Pyridoxine
also known as Pyridoxine
The B vitamin most directly involved in handling protein. B6 is a cofactor in over 100 enzyme reactions, most of them dealing with amino acids — the building blocks the body uses to construct everything from muscle to neurotransmitters. Deficiency is uncommon but real, particularly in chronic alcohol use, kidney disease, and with certain medications.
Recommended daily intake
- Adults 19 50 · 1.3 mg
- Men 51 Plus · 1.7 mg
- Women 51 Plus · 1.5 mg
- Pregnancy · 1.9 mg
- Lactation · 2.0 mg
Upper intake limit
100 mg/day for adults
Signs of deficiency
- Microcytic anemia
- Skin rashes, particularly seborrheic dermatitis
- Cracks at the corners of the mouth
- Depression, confusion, irritability
- Weakened immune function
- More common with chronic alcohol use, kidney disease, autoimmune conditions, and certain medications
- Cofactor for over 100 enzyme reactions, most involving amino acid metabolism
- Required for the body to make serotonin, dopamine, GABA, and other mood-related neurotransmitters
- Required for hemoglobin production
- Supports immune function
- May ease morning sickness in pregnancy — well-supported and recommended by obstetric guidelines
- May ease premenstrual symptoms in some women
- Found in poultry, fish, potatoes, chickpeas, bananas, and fortified cereals
- P5P (pyridoxal-5-phosphate) is the active form — preferred for people with certain genetic variants who don't convert standard B6 well
Long-term high-dose B6 (typically over 100 mg daily for months to years) can cause irreversible nerve damage — peripheral neuropathy with numbness, tingling, and balance problems
Most cases of B6 toxicity have come from supplementation, not food
Some over-the-counter products combine B6 above safe long-term levels — check labels
Use caution with levodopa (Parkinson's medication) — B6 reduces its effectiveness
Use caution with phenytoin and other anti-seizure medications — B6 can lower their levels
High-dose B6 may interact with chemotherapy drugs
Generally safe at RDA-level doses from food and standard multivitamins
Research
- Two-step bioconversion of pyridoxal 5'-phosphate from pyridoxine through cofactor regeneration and pyridoxine 5'-phosphate oxidase evolution.
- Should PNPO Deficiency Be Treated In Utero? Clinical Findings From Prenatal Pyridoxine Therapy.
- Repurposing Hetrombopag for Multiple Myeloma by Targeting PNPO: A Celastrol-Inspired Approach.
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