You cannot just take magnesium alone; it lives in relation to other vitamins and minerals such as Calcium and Vitamin D, Vitamin K, etc. and taking random supplements without working with a doctor can be quite dangerous.

http://www.magnesiumeducation.com/fi...tio-3-1-12.pdf

Too, there are multiple types of magnesium and what one finds and buys "cheap" in the grocery/drug store (and even health food stores) is likely one of the kinds where too much will wreck one's bowels.

9 Common Types of Magnesium Explained - Global Healing Center

Little pills (or horse pills :-) are not found in nature and unless you have a medically measured deficiency, playing with supplements can be dangerous. I work with a good site and figure out how to eat my supplements, naturally.

The World's Healthiest Foods