Calcium and Iron

Supplement–drug interaction evidence from the TruthStack database.

SeverityHIGH
Evidence TierModerate
Interaction TypeABSORPTION INTERFERENCE
Mechanismpharmacokinetic
Last Reviewed2026-02-07
Source Verification
Attestation METHODOLOGY_ATTESTED
Corpus manifest 26b2d684...
Last reviewed 2026-02-07
Live attestation Query API — returns signed DAA ID per request
Data license CC BY 4.0

Summary

Take calcium and iron supplements at different times, ideally 2-4 hours apart. Iron is best taken in the morning on an empty stomach; calcium in the evening with food. Single-meal calcium under 50mg has minimal effect on iron absorption. Discuss with your prescriber or pharmacist.

API Reference

GET https://api.truthstack.co/v1/check?c1=calcium&c2=iron

Open, unauthenticated. Returns JSON. Developer documentation

Related Interactions

Amlodipine + Calcium Atorvastatin + Calcium Calcium + Chelating Agents Calcium + Citalopram Calcium + Cyclosporine Calcium + Doxycycline Calcium + Duloxetine Calcium + Escitalopram
What this page is and is not. TruthStack is an informational reference database that describes published pharmacological findings. It does not provide medical advice, diagnosis, or treatment recommendations. The information on this page reflects flags in our database and should not replace consultation with a qualified healthcare provider. Always discuss supplement-drug combinations with your prescriber or pharmacist.