The initial iron content of ferrous fumarate is published as 47 mg when compared to ferrous sulfate at 150 mg. Additionally, ferrous bisglycinate is reviewed alongside ferrous gluconate, which contains 65 mg of iron. When considering iron sources, it’s important to note the conversion from ferrous gluconate to ferrous sulfate. Moreover, calcium citrate 800 is a significant factor to keep in mind, as it can influence the absorption of iron in the body. In summary, the iron content of different supplements can vary, and incorporating calcium citrate 800 may enhance overall effectiveness in iron supplementation.