Total body magnesium content in an adult person weighing 70 kg is 1000 mmol. The daily magnesium requirement is 0.15 to 0.20 mmol/kg, and the average dietary magnesium intake is 20 mmol/d. The normal range of plasma magnesium levels is 0.65 to 1.20 mmol/L, out of which 30% is bound to albumin. Kidneys are the key regulator of magnesium homeostasis.
Mg2+ is a catalyst for glycolytic enzymes, respiratory enzymes, and enzymes responsible for nucleic acid synthesis. It is involved in contraction of cardiac myocytes and platelet stabilization (preventing platelet activation).