What it does
Needed for nerve function, DNA production and healthy red blood cells.
Possible deficiency symptoms
Deficiency can cause fatigue, anemia, numbness or tingling, balance difficulties and memory changes. Nerve symptoms can occur without anemia.
Food sources
Fish; meat; eggs; dairy; foods fortified with B12. Unfortified plant foods are not reliable sources.
Supplement forms
Cyanocobalamin, methylcobalamin, hydroxocobalamin and adenosylcobalamin. The reason for low B12 helps determine the route of treatment.
Before taking a supplement
Discuss persistent tingling or balance changes promptly. Folate supplementation can obscure an anemia sign of B12 deficiency.
Questions for your visit
Could my diet, medicines, absorption or another condition explain my concern? What evidence would support treatment, and how would we check whether it helps?
Names you may see
Vitamin B12 (Cobalamin) · Cobalamin · B12 · cobalamin
Sources & perspective
This is an editorial adaptation of the Purser Wellness nutrient reference app. Purser teaching connections are labeled separately from clinical interpretation. Private cases and individual treatment protocols are not reproduced.
Use the public resources below for additional context.
NIH Office of Dietary Supplements: Vitamin B12 (Cobalamin)
