Rankings / Essentials — Vitamins & Minerals
Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin)
Essentials · Vitamin
Tier A+
Bottom line
Read Off Label grades Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) as A+ (8.4/10) based on strong evidence, strong benefit magnitude, and a low-risk safety profile.
Deficiency is common and underdiagnosed: 10-30% of adults over 50 lose intrinsic factor or parietal cell function; metformin and PPIs accelerate it.
Typical use: 2. — OTC (oral / sublingual); Rx.
What this is
Deficiency is common and underdiagnosed: 10-30% of adults over 50 lose intrinsic factor or parietal cell function; metformin and PPIs accelerate it. Methylmalonic acid (MMA) is more sensitive than serum B12 for tissue deficiency. Cyanocobalamin and methylcobalamin both work in non-deficient people; hydroxocobalamin is preferred for true B12 malabsorption.
Mechanism
Cofactor for methionine synthase (remethylates homocysteine to methionine — the source of methyl groups for DNA/histone/neurotransmitter methylation) and methylmalonyl-CoA mutase (odd-chain fatty acid and BCAA catabolism)
Dose & route
2.4 mcg/day RDA; 500-1000 mcg/day oral or sublingual methyl-/hydroxocobalamin typical; 1 mg IM monthly for malabsorption
Citations
- https://pubmed.ncbi.nlm.nih.gov/23356638/
- https://pubmed.ncbi.nlm.nih.gov/30060638/
- https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
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Common questions
- Does Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) work?
- Read Off Label rates the evidence for Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) as Strong and the benefit magnitude as strong, producing an overall grade of A+ (8.4/10). Deficiency is common and underdiagnosed: 10-30% of adults over 50 lose intrinsic factor or parietal cell function; metformin and PPIs accelerate it.
- Is Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) safe?
- Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) has a low risk profile in published human data. Legal status: OTC (oral / sublingual); Rx (IM hydroxocobalamin for malabsorption). This is not medical advice — see the disclaimer.
- What is the typical dose for Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin)?
- 2.4 mcg/day RDA; 500-1000 mcg/day oral or sublingual methyl-/hydroxocobalamin typical; 1 mg IM monthly for malabsorption
- How does Vitamin B12 (methylcobalamin / cyanocobalamin / hydroxocobalamin) work?
- Cofactor for methionine synthase (remethylates homocysteine to methionine — the source of methyl groups for DNA/histone/neurotransmitter methylation) and methylmalonyl-CoA mutase (odd-chain fatty acid and BCAA catabolism)
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.