Iron Supplement. Gradual and gentle iron absorption. Choose the Feosol Iron that's right for you. Each form of iron is absorbed differently by the body, depending on the individual, the form of iron and diet. Feosol Natural Release: Type of Iron: Carbonyl iron; Benefit: gradual and gentle iron absorption. Absorb Iron Gradually, Naturally: Feosol Natural Release with carbonyl iron is a pure form of iron which is naturally regulated by the body, making it gentle on the system. Gradual absorption also makes carbonyl one of the safest forms of iron available. Feosol Natural Release with carbonyl iron requires no additives for a gradual and gentle absorption of iron. Iron supplements that claim to have a slow release mechanism usually rely on a chemical coating to slow absorption. Progressive Absorption Means Low Side Effects: Because of the unique way that carbonyl iron is absorbed by your system, common side effects associated with iron supplements may be minimized. (These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.)