GLOSSARY

Methylcobalamin is the methylated cobalamin cofactor for methionine synthase; a coenzyme name does not establish universal product superiority.

Cobalamin names the B12 family. Methylcobalamin and adenosylcobalamin are coenzyme forms; cyano- and hydroxocobalamin can be converted. Active branding does not establish superiority for everyone. Route, amount and deficiency cause matter, and oral products and injectable medicines are not interchangeable solely because their names are related; clinical circumstances govern their use.

Cofactor broadly names a nonprotein enzyme helper, while coenzymes are organic helpers. Several B vitamins become parts of coenzymes after conversion; vitamins do not all work in the same way. Coenzymes are necessary, but supplement amount alone does not set pathway speed: enzyme supply, substrates and energy-demand regulation also impose limits.

Food-bound B12 must first be released, then normally uses gastric intrinsic factor and absorption in the terminal small intestine. A small fraction can also enter by an independent pathway. Package amount is therefore not the absorbed amount, and gastric or ileal problems can impair status despite adequate food. These mechanisms help explain why dietary and medical correction strategies can differ.