Hydroxocobalamin

Tier 2 — promising · B12 form · Long-acting · Cyanide antidote · Nitric oxide scavenger

A natural, non-synthetic form of vitamin B12 found in foods, with a half-life 3–5× longer than cyanocobalamin and superior tissue retention due to tighter protein binding. Standard for injectable B12 in the UK, EU, Canada, and most countries outside the USA because it sustains blood levels longer with less frequent dosing. Unlike cyanocobalamin, it scavenges cyanide ions (the approved clinical antidote to cyanide poisoning) and binds excess nitric oxide. Oral absorption is limited without intrinsic factor — sublingual, injectable, or intranasal routes achieve far higher bioavailability for…

Dose: Oral/sublingual: 500–1,000 mcg/day for deficiency correction. Maintenance: 250–500 mcg/day. Injection: 1,000 mcg IM (prescription only).