INS and diabetes mellitus: As reported, the positive findings of magnesium supplement in diabetes mellitus on HbA1c and insulin sensitivity parameters despite patients having magnesium levels within the normal range at the entry of the study and with no significant change at the end of the study can be explained by the fact that most (99%) of magnesium in the body is stored in the cell and serum magnesium constitute only 1% of the total magnesium in the body20.