Highly dosed vitamin B12 from 3 sources (MHA formula) | Biogena Vitamin B12 1000 Superior contains the three naturally occurring vitamin B12 compounds in the body in a perfectly balanced ratio: methylcobalamin (M), hydroxocobalamin (H) and adenosylcobalamin (A). Methylcobalamin and adenosylcobalamin are the forms of vitamin B12 that are active as coenzymes.