Vitamin B12
What it is
Essential for nerve function, energy metabolism, and red blood cell production. About 20% of adults over 60 and 50%+ of vegans are deficient. Absorption declines with age and is impaired by metformin and acid-blocking medications. Deficiency causes fatigue and — if untreated for years — irreversible nerve damage. Sublingual or methylcobalamin forms absorb better in people with absorption problems.
Dose
500–1,000 mcg/day sublingual methylcobalamin or cyanocobalamin; confirm deficiency with serum B12 + MMA test
Time of day & tips
Sublingual: dissolve under the tongue for best absorption. Take in the morning as B12 can be energising. Space 2 hours from antacids and PPIs, which reduce absorption.
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