Yes, magnesium will cause loose stools if taking too much too soon. Start slowly when taking it internally. In order to get therapeutic levels quickly, consider transdermal magnesium, aka Mag Oil, in addition to your Citrate. This concoction is Magnesium Chloride flakes, dissolved in water, which is sprayed on the skin. Because there is no digestive involvement, it will not affect your bowel movements. I purchase my own mag flakes (Swanson's does carry) and make my own mag oil, but there are companies that sell mag oil. Search transdermal magnesium therapy, and you'll find information on this great method of getting magnesium levels up quickly, and safely. Considering it is estimated that 75-85% of the population is mag deficient, it is likely, especially after reading your post, that you are deficient. Being deficient in magnesium has a cascade effect on other nutrients becoming deficient as well. Magnesium is needed for over 300 functions in the body. Hope this helps.