·       Magnesium is a predominantly intracellular ion.

·       Normal range = 1.7-2.0 mg%

·       Complexed part is with citrate, phosphates, bicarbonate, oxalates

·       Magnesium, Calcium and H+ ions compete for the same site on the Albumin for binding.

·       Magnesium absorption from the gut is load dependent, i.e irrespective of whether it isneeded or not therefore no protection against hyperMg++ as seen in antacid therapy.

·       Urinary loss of magnesium is dependent on the intake (N=100mg/day; range 25-250).Fractional excretion of magnesium is halfway between Na and K. Sodium and Cl = 1%, potassium=10 , Magnesium =4%.