In a study involving 76 adults published in the Natural Medicine Journal, researchers evaluated the effectiveness of magnesium supplements to reduce the risk of developing kidney stones. The subjects were divided into three groups; two of the groups took 120 milligrams of either magnesium oxide or magnesium citrate three times a day for eight weeks, while a control group took a placebo. A urine analysis was performed on each participant at the start of the study and after eight weeks.

The researchers found that magnesium citrate significantly reduced 24-hour urine oxalate levels and calcium oxalate supersaturation—two indicators of kidney stone risk. A reduction in the urinary excretion of calcium is believed to reduce the chances of developing kidney stones.