Vitamin B12
Commonly used for
EnergyFocusHealthy Aging
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What is it? / Overview
Vitamin B12 is essential for healthy nerves, red blood cell production, and DNA synthesis. People consuming little or no animal products or those with reduced absorption are at greater risk and supplementation effectively restores levels in most cases.
How is it used? / Administration
Form: Methylcobalamin or cyanocobalamin (both effective for most people)
Typical dose studied: 500–1,000 mcg/day orally when deficient or at risk
Timing: Morning or with any meal
Oral supplementation effective for most deficiencies. Vegans require routine B12 supplementation. Rare, narrow cautions worth knowing rather than acting as a matched restriction: cobalt hypersensitivity (a component of the cobalamin molecule) and Leber hereditary optic neuropathy (a rare genetic condition where high-dose cyanocobalamin specifically, not methylcobalamin, may worsen vision) — both are uncommon enough that they're noted here rather than tracked as a blocking condition.
How well does it work? / Evidence
✓ Well-established
Who should avoid it?
Interacts with: Metformin and PPIs reduce absorption — flag B12 monitoring
Already taking it? Confirm deficiency corrected before continuing high-dose therapy indefinitely.
Research & references
O'Leary F, Samman S. (2010). Vitamin B12 in Health and Disease. Nutrients. NIH Office of Dietary Supplements: Vitamin B12 Fact Sheet. Allen LH. (2009). Causes of Vitamin B12 Deficiency.
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