Calcium

A mineral supplement used to support bone health, taken as calcium carbonate or calcium citrate among other forms.

Supplement

What it is

Calcium builds and maintains strong bones and also supports muscle movement, nerve communication, blood vessel function, and hormone release. The two most common supplement forms are calcium carbonate and calcium citrate. Food (particularly dairy products) is the preferred source; supplements are used when dietary intake isn't enough.

Food and timing considerations

Calcium carbonate is absorbed best when taken with food. Calcium citrate is absorbed well either with or without food, and is often recommended for people with lower stomach acid. Calcium is generally absorbed best in doses of 500 mg or less at a time, so larger daily amounts are often split across two or more doses.

Known interaction categories

Insufficient evidence
Informational
Monitor
Use caution

Published interaction pages on this site

Sources

Calcium — MedlinePlus, U.S. National Library of Medicine

Last reviewed 2026-08-22

Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.