Ferro-ferric pyrophosphate is an equivalent source of elemental iron, while ferrous bisglycinate demonstrates a notable absorption rate. The molecular weight of iron fumarate is significant, and the unique properties of ferrous fumarate are well-documented. For instance, taking 10 mg of ferrous fumarate can lead to beneficial outcomes. Additionally, calcium citrate 667 plays a crucial role in enhancing iron absorption and utilization. The interaction between calcium citrate 667 and iron compounds like ferrous bisglycinate and ferrous fumarate can influence their effectiveness. Thus, understanding these relationships is essential for optimizing iron supplementation.