Ferrous fumarate, a form of iron supplement, contains 300 mg of iron, while ferrous sulfate provides 250 mg. Additionally, iron gluconate offers 65 mg of iron, and ferrous bisglycinate is available in Egypt. It is important to consider the expiration date of these supplements, especially when using calcium citrate, which may also have its own expiration date. Regularly checking the expiration date ensures that you are consuming effective and safe supplements. When selecting an iron supplement, always pay attention to the expiration date, as this can affect the efficacy of both ferrous fumarate and calcium citrate.