Calcium and Magnesium
Compete for absorption at very high single doses; keep intake balanced rather than mega-dosing one.
Calcium
The primary structural mineral of bones and teeth.
Magnesium
A master mineral involved in 300+ enzyme reactions.
Combine with care
These can compete for absorption or interact; separate the timing or keep the doses balanced rather than taking large amounts together.
How to take them
Calcium
- Dose
- 500–1,000 mg per day from supplements, only to fill dietary gaps
- Timing
- Citrate any time; carbonate with food. Split doses above 500 mg.
Magnesium
- Dose
- 200–400 mg elemental magnesium per day
- Timing
- Evening for sleep support; with food to reduce GI upset
Frequently asked
Can you take Calcium and Magnesium together?
It's best to separate them across the day or balance the doses rather than taking large amounts at the same moment. Compete for absorption at very high single doses; keep intake balanced rather than mega-dosing one.
What's the best time to take Calcium and Magnesium?
Space them out. Calcium: Citrate any time; carbonate with food. Split doses above 500 mg.. Magnesium: Evening for sleep support; with food to reduce GI upset.
How do Calcium and Magnesium interact?
Use with care: Can compete, deplete, or interact; time or balance them. Compete for absorption at very high single doses; keep intake balanced rather than mega-dosing one.
Related pairings
Calcium + Vitamin D3
Vitamin D3 is required to absorb dietary and supplemental calcium.
Calcium + Iron
Calcium taken at the same time inhibits iron absorption; separate them by at least two hours.
Calcium + Vitamin K2
K2 activates the proteins that bind dietary calcium into the bone matrix.
Magnesium + Vitamin D3
Magnesium is required to convert vitamin D into its active form, so low magnesium blunts D3's benefits.