Ferric pyrophosphate is an iron coordination entity composed from Fe(3+) cations and diphosphate(4-) anions in a 4:3 ratio. It contains a diphosphate(4-). Ferric pyrophosphate is an iron replacement product. Free iron presents several side effects as it can catalyze free radical formation and lipid peroxidation as well as the presence of interactions of iron in plasma. The ferric ion is strongly complexed by pyrophosphate. It presents an increasing interest as this insoluble form can be milder in the gastrointestinal tract and present higher bioavailability.