Adenosylcobalamin (B12)
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Adenosylcobalamin (B12). Mitochondrial coenzyme form of B12 — partners with methylcobalamin for full B12 status.
How it works. Cofactor for methylmalonyl-CoA mutase in mitochondria — required for fatty acid and BCAA metabolism.
What the research supports. 1 graded claims. Strongest: Lowers methylmalonic acid (functional B12 marker) (moderate).
How much to take. Typical dose: 1000 mcg sublingual.
Side effects and interactions. 1 medication interaction listed. Serious: Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing.
Stacking. Pairs well with A high-quality multivitamin, Omega-3 (EPA/DHA).
Common forms. Available as Capsule or softgel, Sublingual tablet or liquid, Methylated active form for sensitive individuals, Multivitamin matrix.
Key studies. 8 studies cited. The strongest are listed with links to PubMed.
Community. Experiences from people who have tried Adenosylcobalamin (B12). Anecdotes are not medical advice.
Adenosylcobalamin (B12). Mitochondrial coenzyme form of B12 — partners with methylcobalamin for full B12 status.
What it is
Mitochondrial coenzyme form of B12 — partners with methylcobalamin for full B12 status.
Food sources
Goals
How it works
Cofactor for methylmalonyl-CoA mutase in mitochondria — required for fatty acid and BCAA metabolism.
Pathways
- Methylmalonyl-CoA mutase
- Mitochondrial energy metabolism
Effects
- ↓methylmalonic acid (functional B12 marker) decreases
What the research supports
Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.
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Side effects & interactions
Common side effects
- Adenosylcobalamin (B12) is generally well-tolerated at evidence-based doses
- Mild GI discomfort (nausea, loose stools, or bloating) possible at higher intakes
- Headache or transient fatigue reported by a small fraction of users
Serious
- Discontinue and seek medical advice if symptoms are severe, persistent, or include difficulty breathing
Medication interactions
Always disclose Adenosylcobalamin (B12) use to your prescriber — additive, antagonistic, or pharmacokinetic interactions are possible.
Check any supplement–medication combination with your pharmacist before starting.
Combines with
Pairs well
- A high-quality multivitaminCovers micronutrient cofactors that support most supplement pathways.
- Omega-3 (EPA/DHA)Foundational anti-inflammatory support that complements most regimens.
Common forms
- Capsule or softgel
- Sublingual tablet or liquid
- Methylated active form for sensitive individuals
- Multivitamin matrix
Key studies
8 studies cited in total.
Opens current human and preclinical literature matching Adenosylcobalamin (B12) and "Lowers methylmalonic acid". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching Adenosylcobalamin (B12) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching Adenosylcobalamin (B12) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.
Discussion
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