Table 5.

Different magnesium formulations.

Magnesium Supplement	Elemental Magnesium (Percent)	Bioavailability (as Fractional Absorption of the Administered Dose)	Bioavailability (Relative Comparison)	Tolerability (Diarrhea)
Magnesium Oxide	60	4%	Extremely low	++
Magnesium Carbonate	45	*	Extremely low	*
Magnesium Hydroxide	42	4%	*	++
Magnesium Citrate	16	12%	Good	++
Magnesium Lactate	12	12%	Excellent	+
Magnesium Chloride	12	12%	Good	+
Magnesium Aspartate	10	*	*	*
Magnesium Sulfate	10	4%	*	++
Magnesium Gluconate	5	*	Good	±

Data obtained from Guerrera et al [46], Firoz M [47], Ranade [48], Epocrates [49], The Schrier Atlas of Diseases of the Kidney [50]. * Data could not be obtained. ++ Indicates higher incidence of diarrhea, + indicates lesser incidence of diarrhea. ± Indicates equivocal incidence of diarrhea.