Moderate evidenceVitamins & minerals

Hydroxocobalamin

The B12 form used for injections in much of Europe, because it stays in the body longer than cyanocobalamin. As an oral supplement it corrects deficiency like any other form, with no proven edge.

Evidence last reviewed: August 2026

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What the science says

Corrects vitamin B12 deficiency Moderate evidence
A Cochrane review of 3 randomized trials (153 people) found that oral B12 around 1000 µg/day normalised serum B12 concentrations as well as intramuscular injection — the route hydroxocobalamin is normally given by — at lower cost. The evidence was rated low quality due to small trial size.
No superiority over the other B12 forms Moderate evidence
A review of cobalamin metabolism found no basis for ranking hydroxocobalamin above cyanocobalamin for prevention or treatment of deficiency; its advantage is pharmacokinetic (slower clearance after injection), which matters for injection intervals rather than for daily tablets.

Dosage & safety

Studied doseOral supplements typically supply 1000 µg/day. Medical injections are usually 1000 µg on a schedule set by a doctor. The cyanide-antidote use (5 g intravenously in smoke inhalation) is a hospital emergency treatment with no relation to supplements.

SafetyWell tolerated; high doses can tint urine pink or red. As with any B12, treating symptoms without establishing the cause of a deficiency can delay diagnosis. Hydroxocobalamin is preferred over cyanocobalamin in people with Leber's hereditary optic neuropathy and in renal impairment, where the cyanide moiety is a theoretical concern.

Scientific references

Oral vitamin B(12) versus intramuscular vitamin B(12) for vitamin B(12) deficiency
Wang H, Li L, Qin LL — Cochrane Database Syst Rev, 2018
Cobalamin coenzyme forms are not likely to be superior to cyano- and hydroxyl-cobalamin in prevention or treatment of cobalamin deficiency
Obeid R, Fedosov SN, Nexo E — Mol Nutr Food Res, 2015

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