Comparison guide

Which vitamin B12 should you take?

Every form of B12 corrects a deficiency, because whatever you swallow is stripped and re-converted inside your cells. Reviews find the “active” coenzyme forms unlikely to beat cyanocobalamin, so what matters is taking enough if you are vegan, older or absorb B12 poorly — not which label you buy.

The options, compared

Option	Evidence	Best for	The honest note
Vitamin B12	Strong evidence	Most people	Cheap, stable cyanocobalamin at 250–1,000 mcg/day reliably corrects and prevents deficiency, which makes it the standard for vegans and for older adults who absorb food-bound B12 poorly.	View
Methylcobalamin	Moderate evidence	Fine if you prefer it	Corrects deficiency reliably at 500–1000 µg/day, but the claim that it is better absorbed or used than cyanocobalamin is not supported: absorbed B12 is re-converted in your cells regardless of form.	View
Adenosylcobalamin	Limited evidence	No proven reason to choose it	Sold as “mitochondrial B12”, yet no randomized trial has compared it with another form on any clinical outcome. Its 1000–3000 µg label doses are not studied doses.	View
Hydroxocobalamin	Moderate evidence	Injections and kidney impairment	Its edge is slower clearance after injection, which matters for injection intervals rather than daily tablets. It is preferred over cyanocobalamin in renal impairment and Leber's hereditary optic neuropathy.	View

Our verdict

Standard cyanocobalamin is cheap, stable and adequate for almost everyone, especially if you are vegan, older, or on metformin or a long-term proton-pump inhibitor. Methyl-, adenosyl- and hydroxocobalamin are reasonable alternatives, but their claimed advantages are not demonstrated in healthy people. If you are not deficient, no form will raise your energy, and anemia or nerve symptoms need a diagnosis, not just a supplement.