Iron bisglycinate vs ferrous sulfate
Ferrous sulfate is the form most public-health programs have used. Ferrous bisglycinate is a chelate that many people tolerate with less stomach upset. A review of iron formulations in children describes real trade-offs and does not turn a chelate into a do-it-yourself anemia treatment. Compare elemental milligrams, take iron away from calcium, tea, and coffee, and get a ferritin or a clinician involved before a long course.
Both ferrous bisglycinate and ordinary ferrous sulfate are ways of delivering elemental iron. The salt weight on the front of the bottle is the wrong number to compare. Iron dosing in trials and guidelines is written in elemental milligrams.
What we can and cannot say
A 2026 narrative review of iron therapy in children walks through efficacy, safety, and formulation-specific trade-offs (PMID 41562673). It is about pediatric deficiency, not a licence for adults to pick a chelate from a shelf and skip follow-up. Stomach upset, constipation, and a metallic taste are the usual sulfate complaints. Bisglycinate is sold as the gentler option. Gentler does not mean the deficiency is gone.
How to take it if a clinician has said you need it
The NIH iron fact sheet is the reference for dietary allowances and upper limits, and for the interactions that block absorption. Calcium, tea, and coffee taken at the same time reduce what you absorb. Vitamin C with the dose is the old practical pairing. People who are pregnant, who have inflammatory bowel disease, or who have been told their iron is high should not start either form from an article.
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