Magnesium Oxide for Leg Cramps

Formulations and Dosing

Magnesium oxide contains more elemental magnesium than other salts but has lower bioavailability compared to organic forms like magnesium citrate, with organic magnesium salts (citrate, glycinate, aspartate) recommended over inorganic forms like magnesium oxide due to better bioavailability 1
Typical dosing of magnesium oxide for leg cramps ranges from 500-1000 mg daily 1
For hypomagnesemia, magnesium oxide is commonly given as 12-24 mmol daily (approximately 480-960 mg), often at night when intestinal transit is slowest 2

Magnesium supplementation should be avoided in patients with significant renal impairment (creatinine clearance <20 mL/min) due to risk of hypermagnesemia, with the American Gastroenterological Association recommending caution in such cases 3, 1

If using magnesium for leg cramps, consider starting with a lower dose (300-500 mg daily) and increasing if necessary, as recommended by the American Gastroenterological Association 3, 1
Taking magnesium at night when intestinal transit is slower for better absorption is suggested, based on findings published in Gut 2

For erythromelalgia-associated leg cramps, high-dose magnesium (2 g every 2-3 weeks, orally or intravenously) has been suggested but with limited evidence, according to the Mayo Clinic Proceedings 4