Calcium and Magnesium
Last updated: August 9, 2026
These two compete for absorption when taken in large amounts at the same time.
Short answer
You can take both — this is a same-meal absorption effect, not a reason to avoid either nutrient. Spacing the two apart in the day is usually enough.
Why Calcium and Magnesium compete
Calcium's page says: Very high daily calcium intakes can work against magnesium absorption. This one depends on the total daily amount, not on how far apart the two are taken.
Magnesium's page says: Magnesium and calcium can work against each other at very high daily intakes. It's the ongoing daily amount that matters here, not the gap between them.
What this means in practice
Spacing your doses of Calcium and Magnesium by a couple of hours — rather than taking them in the same pill or the same meal — is usually enough to stop them from competing for absorption. At the amounts found in ordinary food, without concentrated supplement doses, this generally isn't something to plan around.
Learn more about each nutrient
Frequently asked questions
Can I take Calcium and Magnesium together?
You can take both — this is a same-meal absorption effect, not a reason to avoid either nutrient. Spacing the two apart in the day is usually enough.
Why do Calcium and Magnesium interact?
From Calcium's side: Very high daily calcium intakes can work against magnesium absorption. This one depends on the total daily amount, not on how far apart the two are taken. From Magnesium's side: Magnesium and calcium can work against each other at very high daily intakes. It's the ongoing daily amount that matters here, not the gap between them.
Does timing matter for Calcium and Magnesium?
Yes, somewhat. Taking large supplemental doses of both at the exact same time is when they compete most; spacing them a couple of hours apart reduces that.
Sources
The relationship described above comes from the same nutrient config that runs inside the Tavita app — see the methodology pagefor how it's sourced and verified. This page is educational information, not medical advice; talk to your clinician before changing your supplement routine.