Magnesium is an element that plays an important role in your body. It is a part of many enzyme systems & helps them to function properly. About 70% of magnesium is stored in your bones while 30% circulates in the blood bound to proteins. It is excreted by the kidneys in urine of which some amount is reabsorbed. High levels of magnesium in blood (Hypermagnesemia) is seen in kidney failure & if there is too much intake of magnesium. Low levels of magnesium in blood (Hypomagnesemia) is seen in malabsorption, chronic diarrhea, alcoholism & other conditions.