Can You Take Calcium and Magnesium Together?

May affect absorption

The short answer

Calcium and magnesium compete for absorption. High-dose calcium can reduce magnesium uptake and vice versa.

How to arrange timing

Space these at least 2 hours apart, or take calcium in the morning and magnesium in the evening.

Reference

Reference noted for this combination: NIH ODS 2024

Important context

Whether supplements suit you together also depends on dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.