Iron bisglycinate in this complex is a form that is easier for many to absorb, and it comes with friendly cofactors such as B and C vitamins, which further help increase absorption. Iron bisglycinate is a chelated form of iron with two molecules of the amino acid glycine attached to an iron. This novel type of iron has a higher absorption rate and is absorbed by the cells of the small intestine without the usual irritation and constipation of other forms.