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
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.