Reacted Iron provides 29 mg of elemental iron per serving, ideally formulated. using the amino acid chelate form of iron (ferrous bisglycinate) for enhanced. absorption, optimal utilization and gastrointestinal (GI) comfort. Some. individuals, who take other forms of iron supplements, may experience GI side. effects, including gas, bloating, constipation or a combination of these. symptoms. Supplementing the right form of iron can be key to maintaining. healthy levels within the body and compliance to a supplement regimen.