The first pediatric ferrous bisglycinate chelate is ferrous sulfate at 220 mg, followed by ferrous gluconate and iron fumarate gummies, as well as remedica ferrous fumarate. It is important to note that the absorption rate of calcium citrate plays a crucial role in enhancing iron absorption. By incorporating calcium citrate, the overall absorption rate of calcium citrate can significantly impact the effectiveness of iron supplements. Therefore, considering the absorption rate of calcium citrate is essential when choosing iron formulations for children.