This specially processed cobalamin contains an ion-exchange resin that responds to a certain pH. As the tablet disintegrates, the active nutrient is protected by the resin until it reaches the small intestine where the pH is high enough to allow the resin to release the B12. If the resin were not present the B12 would combine with an R protein in the stomach. If a person has insufficient digestive enzymes it could interfere with the release of cobalamin from the R protein and reduce the amount of vitamin available for absorption. This process can essentially double the absorption of B12.

Intrinsic factor (IF) is a glycoprotein synthesized by the gastric parietal cells. Although it is made and released in the stomach, IF functions in the small intestine. In the small intestine IF binds the cobalamin. The cobalamin-IF complex travels to the ileum, where receptor sites for vitamin B-12 are present. Absorption of the vitamin occurs throughout the entire ileum, especially the distal third.