MODERATE — Monitor Closely
🟡 USE CAUTION — Iron and Calcium may interact. Talk to your doctor before combining.
Evidence level: STRONG
Calcium and iron compete for absorption. Take at different times of day.
Calcium inhibits heme and non-heme iron absorption. May reduce iron absorption by 50-60%.
The interaction between Iron and Calcium is manageable with awareness. Talk to your doctor or pharmacist, especially if you notice any new or unusual symptoms after combining them.
Iron competes with most other minerals for absorption. Take iron on its own — ideally on an empty stomach with vitamin C (orange juice works) for maximum absorption. Take Calcium with a different meal, at least 2-3 hours apart from iron. Never take iron and calcium together — calcium reduces iron absorption by up to 60%.
Risk may increase with: older age, liver or kidney impairment, taking multiple medications, and higher doses of either substance.
Monitor for any new or unusual symptoms when starting this combination. Report changes to your healthcare provider.
Mention this combination at your next appointment. Ask: "Should I adjust timing or doses of Iron and Calcium?" Your doctor may want to monitor specific lab values.
Try spacing these supplements at least 4 hours apart or taking them at different meals. If the interaction involves absorption competition, alternating days may be more effective than simultaneous use.
Calcium and iron compete for absorption. Take at different times of day.
Iron competes with most other minerals for absorption. Take iron on its own — ideally on an empty stomach with vitamin C (orange juice works) for maximum absorption. Take Calcium with a different meal, at least 2-3 hours apart from iron. Never take iron and calcium together — calcium reduces iron absorption by up to 60%.
Monitor for any new or unusual symptoms when starting this combination. Report changes to your healthcare provider.
Try spacing these supplements at least 4 hours apart or taking them at different meals. If the interaction involves absorption competition, alternating days may be more effective than simultaneous use.
Mention this combination at your next appointment. Ask: "Should I adjust timing or doses of Iron and Calcium?" Your doctor may want to monitor specific lab values.
Or browse the full interaction database (121,000+ pairs).