Ferrous sulfate 325 mg, ferrous fumarate 210 mg, and ferrous gluconate 65 mg are common iron supplements used to address iron deficiency. Additionally, ferrous fumarate is often found in various formulations, including Tesco products and Pregnacare. It’s important to note that when taking iron supplements, the absorption of iron can be affected by other substances, such as calcium. For example, calcium d citrate can influence the effectiveness of iron supplementation, so it’s advisable to manage the timing of these supplements. Ensuring proper intake of calcium d citrate along with iron can help maintain an optimal balance of nutrients. Therefore, when considering ferrous fumarate, ferrous sulfate, or ferrous gluconate, one must also take into account the role of calcium d citrate in absorption and overall health.