Is Iron supplement Safe with Calcium supplement?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Do not take calcium supplements within 2 hours of iron supplementation. Schedule calcium with meals and iron between meals for optimal absorption of both minerals.
Why this interaction occurs
Calcium inhibits iron absorption across a wide dose range (300–600 mg). This interaction occurs at the mucosal cell level and affects both ferrous and ferric iron forms. Clinically significant in patients treating iron-deficiency anemia who also require calcium therapy.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 620,762 reports mentioning Calcium supplement. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Calcium supplement + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Iron supplement interactions → · All Calcium supplement interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.