B12 and B-Complex: Who Actually Needs It, and the B6 Trap

Summary

B12 is a genuine, sometimes urgent fix for a defined set of risk groups (vegans, adults over 50, long-term metformin or acid-suppressant users, pernicious anaemia, post-GI-surgery) — but in most of those people the cause is **malabsorption, not low dietary intake**, so eating more meat won't fix it and a cheap **cyanocobalamin** supplement will; meanwhile "B vitamins for energy" sold to the already-replete is empty marketing, and the high-dose **B6** baked into many B-complex and "energy" products is a real, under-publicised nerve-damage hazard. ---