Vitamin B12 as methylcobalamin
The absorption of vitamin B12 from food and diet is a complex and sensitive process. Because of the safety of vitamin B12 supplementation and the often difficult absorption of B12 from food and supplements, Multivitamin OPTIMUM contains no less than 12.5 mcg vitamin B12 (500% RDA) per tablet in the biologically active form methylcobalamin. Many B12 products and multivitamins contain the cheaper, synthetic form of vitamin B12, cyanocobalamin. This form does not occur as such in nature and must first be converted by the body to the active forms. The cyanide part is separated from the cobalamin by enzymes and then eliminated by the body. Studies show that vitamin B12 in the form of the active methylcobalamin has a higher bioavailability than, for example, cyanocobalamin.