Multivitamins, including ferrous sulfate, have been compared with ferrous gluconate and ferrous bisglycinate. When evaluating iron supplementation, studies indicate that iron bisglycinate may offer advantages over ferrous sulfate and ferrous gluconate, particularly when considering the equivalent dosage of 27 mg. Additionally, ingredients such as calcium citrate play a vital role in enhancing the absorption of iron. It is important to note the purity of the formulations, especially with products like Opurity Calcium Citrate Plus, which can improve overall nutrient absorption. In summary, when choosing between ferrous sulfate, ferrous gluconate, and iron bisglycinate, one should also consider the benefits of supplements like Opurity Calcium Citrate Plus for optimal health outcomes.