Vitamins & minerals
Vitamin B12
Names you may see: cobalamin methylcobalamin cyanocobalamin adenosylcobalamin B12
The quick take
Vitamin B12 supports normal red-blood-cell formation, DNA synthesis and nervous-system function.
A closer look
What forms will I see on a label?
Cyanocobalamin and methylcobalamin are common forms. The form alone does not establish that one product will work better for everyone.
Why people use it
People choose B12 to address low intake or absorption concerns, including on vegan diets. It is also marketed for energy, although extra B12 is not a general performance booster.
These are common goals and marketing uses. The evidence section below explains what research supports.
What does the evidence tell us?
People with low intake or impaired absorption may need supplementation. B12 does not reliably improve energy or endurance when status is already adequate.
What should I know before using it?
Some medicines and digestive conditions affect B12 absorption. Suspected deficiency requires assessment because the appropriate treatment varies.
Sources & further reading
NIH Office of Dietary Supplements ↗
Content reviewed: September 30, 2026
General educational information. Follow the product label and seek individual advice when needed.