Magnesium is an essential mineral, and is an electrolyte which plays a key role in numerous bodily processes. While a good number of foods are rich in Magnesium, deficiencies are very frequent in the standard western diet. Magnesium Malate is a type of magnesium supplement made by combining elemental magnesium with malic acid and contains 15% elemental magnesium by weight. (1500 mg contains 225 mg of elemental magnesium.)