How much ferrous sulfate is absorbed? The ferrous fumarate 210 mg tablets and the ferrous fumarate 324 mg tablets are both options for supplementation. When comparing ferrous gluconate and ferrous sulfate, which one is better? Additionally, ferrous fumarate is available in a 50 mg dosage. It’s important to consider factors such as calcium citrate and its relation to GERD, as these elements can influence the absorption of iron supplements. For those with GERD, the interaction between calcium citrate and iron supplements is worth noting, especially when determining the optimal form of iron for absorption. Ultimately, understanding how much ferrous sulfate is absorbed and how it compares to ferrous fumarate and ferrous gluconate can help individuals make informed decisions regarding their iron supplementation while considering the effects of calcium citrate on GERD.