There are many different forms of magnesium, and no compelling data about absorption differences. However, there are reported differences in how different forms affect the gastrointestinal tract. Forms and functions of some of these include: <br/><br/> • Oxide: tends to firm stools in some individuals and loosen stools in others<br/> • Glycinate: a very gentle form of magnesium that is easier on the system<br/> • Citrate: tends to loosen stools<br/> • Sulfate: tends to loosen stools<br/> • Chloride: tends to loosen stools.<br/> <br/> Individual results may vary. Your physician should recommend the form that’s right for you. <br/><br/> Magnesium supplements usually have their beginning as minerals that have been influenced by our environment. For that reason, the purity of magnesium raw materials is important. Magnesium, like calcium, can have undesirable impurities present. Kirkman’s magnesium is Ultra Tested, which means it is tested for more than 950 environmental contaminants, the highest standard of purity testing in the world.