Translations:Cyanocobalamin/21/en

Historically, the physiological form was initially thought to be cyanocobalamin. This was because hydroxocobalamin produced by bacteria was changed to cyanocobalamin during purification in activated charcoal columns after separation from the bacterial cultures (because cyanide is naturally present in activated charcoal). Cyanocobalamin is the form in most pharmaceutical preparations because adding cyanide stabilizes the molecule.