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Vitamin B12

cyanocobalamin / methylcobalaminNot a peptide · vitaminGI/Bone/Other

Not a peptide — a corrinoid vitamin. Listed because it is commonly discussed alongside them.

Evidence grade
AFDA-approved Rx (labeled use)
Cardiovascular · 0–5 · separate axis
2
Read first · not dosing instructions

Educational and research reference only. Not medical advice, not a recommendation, and not dosing instructions for any person. Figures are reported from the cited source and may be wrong or out of date. Research peptides are not approved for human use. Adults 18+. Consult a licensed physician before any decision about your health.

PurposeSupport / Adjunct
MechanismCofactor for methionine synthase and methylmalonyl-CoA mutase; required for haematopoiesis, myelin maintenance and homocysteine metabolism.
EffectsCorrects deficiency. Injected forms bypass the intrinsic-factor absorption pathway, which is what makes them useful in pernicious anaemia.
DosingFor pernicious anaemia the labelled regimen is 30–50 mcg intramuscularly or subcutaneously daily for at least two weeks to a total of 1,000–5,000 mcg, then 100 mcg monthly as maintenance. Higher single doses are common in practice.
Bottom lineAn approved, cheap and genuinely useful correction for a real deficiency — and a placebo for everything else it gets sold for.
Batches on filenone

No tested batches on file.

Read with

The library records no pairings for this entry.

Cautions & interactions

Generally well tolerated. Mild injection-site pain and rare allergic reaction. Supplementation can mask the haematological signs of deficiency while neurological damage progresses, so a documented B12 level before treatment matters.

Metformin reduces B12 absorption by interfering with calcium-dependent intrinsic-factor binding; subnormal levels appeared in about 7% of metformin patients in trials, and B12 should be measured every two to three years on long-term therapy. Proton-pump inhibitors and H2 blockers also reduce absorption.

CV 2 of 5 — Lowers homocysteine, but homocysteine-lowering trials have not translated into reduced cardiovascular events. Treat the marker change as a marker change.