B12 10mg

Vitamin B12 exists in several forms, and methylcobalamin is the one that functions directly as a cofactor without requiring intracellular conversion, which distinguishes it from cyanocobalamin in experimental work. It supports methionine synthase in the remethylation of homocysteine to methionine, the reaction that regenerates S-adenosylmethionine and links B12 status to methylation capacity generally. The cobalt-corrin structure makes it light-sensitive, so the amber vial and dark storage are functional requirements rather than convention.