Iron (Ferrous Bisglycinate)
Ferrous bisglycinate is an amino acid chelate form of iron with superior bioavailability & gastrointestinal tolerability compared to traditional iron salts; it is the first-line choice for iron deficiency anemia supplementation, particularly in pregnancy.
Evidence last reviewed: 04 Apr 2026
- •known iron overload conditions
- •certain gastrointestinal disorders
- •allergic reactions to iron supplements
Moderate evidence indicates that ferrous bisglycinate significantly improves hemoglobin levels and has better absorption compared to traditional iron salts. However, more research could further clarify its long-term effects and optimal dosing.
Hemoglobin & ferritin concentrations in iron deficiencyPregnant women and children with iron deficiency · systematic review and meta-analysis of RCTsModerate
Meta-analysis of 17 RCTs found ferrous bisglycinate produced significantly higher hemoglobin concentrations & fewer gastrointestinal adverse events compared to other iron supplements in pregnant women; ferritin showed a non-significant trend toward improvement; no clear advantage was demonstrated in children.
Iron absorption & bioavailability compared to ferrous sulfateAdults assessed in absorption study · controlled bioavailability studyModerate
A controlled human absorption study found geometric mean iron absorption from ferrous bisglycinate (6.0%) was approximately 4-fold higher than ferrous sulfate (1.7%) in whole-maize meal; absorption from bisglycinate was regulated by iron status & did not exchange with non-heme food iron, indicating a protected chelate pathway.
Forms & usage▾
Take 30 mg of ferrous bisglycinate daily, preferably on an empty stomach for optimal absorption.