Inorganic ferrous salts, this type of iron supplements have higher iron content and cheaper, but they are unstable in nature and are easily affected by other ingredients in food, poor bioavailability and significant gastrointestinal irritation, bad taste. In addition, such iron supplements can cause food deterioration, discoloration and other adverse effects. Since the 1960s, the second generation of iron supplements represented by ferrous lactate, namely small molecular organic acid salts, has appeared. Compared with the first generation of iron supplements, this kind of iron supplements avoid the instantaneous concentration of the drug in the stomach and the irritating effect is greatly reduced. However, it is still a ferrous salt, which is unstable in nature, difficult to produce and store, and easy to produce peculiar smell. In addition, ferrous citrate, ferrous fumarate and ferrous succinate are all second-generation iron supplements.

IngredientFerrous sulphateFerrous citrateFerrous lactateFerrous gluconateFerrous Fumarate
Fe(II) %2022191232.9

New iron supplement
Since the end of the 20th century, in order to pursue new iron supplements with fewer adverse reactions and better absorption, researchers have developed amino acid complex iron, heme iron, polysaccharide iron (Ⅲ) , polypeptide iron Ⅱ complex and iron-rich Yeast and other macromolecular complex iron supplements.