21st Century Iron 65 mg is a mineral supplement containing ferrous sulfate that provides 65 mg of elemental iron per tablet. This gluten-free formula comes in a bottle of 120 tablets and is designed to help prevent and treat iron deficiency. Iron supplementation should be taken under medical supervision. The tablets contain ferrous sulfate 325 mg which provides 65 mg of elemental iron. Common side effects may include stomach upset, constipation or dark stools. It's recommended to take iron supplements with vitamin C to enhance absorption. This product is comparable to Feosol. Pregnant women, menstruating women, vegetarians and athletes may have increased iron needs and should consult their healthcare provider about supplementation.