Iron bisglycinate — The Highly Bioavailable Iron Chelate

Iron bisglycinate is absorbed intact into the enterocytes via the amino acid transport system or peptide transporters, bypassing the regulated non-heme iron pathway (DMT1) that is often inhibited by dietary factors like phytates and polyphenols. Once inside the cell, the chelate is hydrolyzed, releasing ferrous iron (Fe2+) into the labile iron pool. This iron is then utilized for the synthesis of heme and iron-sulfur clusters, which are essential components of the mitochondrial electron transport chain complexes and cytochromes, thereby supporting oxidative phosphorylation and cellular respiration.

Multiple randomized controlled trials have demonstrated the efficacy of iron bisglycinate in treating iron deficiency and anemia. A 2023 systematic review and meta-analysis published in Nutrition Reviews confirmed that ferrous bisglycinate effectively increases hemoglobin and ferritin concentrations in both adults and children. Furthermore, trials have consistently shown that it provides comparable or superior efficacy to ferrous sulfate at lower doses, with a significantly lower incidence of gastrointestinal adverse events.

15–30 mg of elemental iron per day is commonly used for maintenance or mild deficiency, while 60–90 mg per day may be used for clinical iron deficiency anemia. It is often taken on an empty stomach, though its chelated structure makes it less susceptible to absorption interference from food compared to other iron salts.

Iron bisglycinate is generally well-tolerated and exhibits a lower rate of gastrointestinal side effects (such as nausea, constipation, and bloating) compared to traditional iron salts like ferrous sulfate. However, excessive iron supplementation can lead to iron overload, oxidative stress, and toxicity. It is contraindicated in individuals with hemochromatosis or other iron overload disorders, and iron status (ferritin, transferrin saturation) should be monitored during supplementation.

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