This blend of B12 forms supports healthy nerve and mitochondrial function.* Hydroxycobalamin is a precursor of B12 which the body converts to methylcobalamin and adenosylcobalamin. Unlike cyanocobalamin, it lacks the cyanide group. Adenosylcobalamin is an activated form similar to methylcobalamin; while the latter is more prevalent in blood and other fluids, the former is generally stored in cellular mitochondria. It is a cofactor for the metabolism of carbohydrates via the enzyme methylmalonyl-CoA mutase, and optimal levels foster the production of myelin in neuronal cells.*