Calcium and Iron
Supplement–drug interaction evidence from the TruthStack database.
| Severity | HIGH |
|---|---|
| Evidence Tier | Moderate |
| Interaction Type | ABSORPTION INTERFERENCE |
| Mechanism | pharmacokinetic |
| Last Reviewed | 2026-02-07 |
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
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.