Is Zinc Safe with Calcium carbonate?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Do not take calcium carbonate and zinc supplements simultaneously. Separate by at least 2 hours. Consider taking zinc on an empty stomach or at bedtime away from calcium doses.
Why this interaction occurs
Calcium ions at high concentrations competitively inhibit zinc absorption in the intestine through shared transporter pathways. Studies show calcium intakes above 600 mg can reduce zinc absorption by approximately 50% when taken concurrently. Zinc is essential for osteoblast function and bone matrix formation.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 914,008 reports mentioning Calcium carbonate. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Calcium carbonate + 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 Zinc interactions → · All Calcium carbonate interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.