The dose makes the poison. So use a mortar and pestle, or liquid supplements and an eyedropper.

Can you elaborate?

Magnesium is a common laxative in high doses. [https://www.drugs.com/mtm/milk-of-magnesia.html#:~:text=Milk....]

Magnesium Citrate and Oxide specifically.

Magnesium Glycinate is much less likely to be a problem in this way