Magnesium for skeletal muscle cramps
Garrison SR, et al.
Published in Cochrane Database of Systematic Reviews
Methodology
Cochrane systematic review updated with searches on 9 September 2019 of the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, CINAHL Plus, AMED, SPORTDiscus, WHO-ICTRP, ClinicalTrials.gov and ISI Web of Science; randomised trials of magnesium in any form versus no treatment, placebo or other therapy; two authors independently selected trials, extracted data and assessed bias, obtaining participant-level data for four trials including one unpublished.
Key Findings
This Cochrane review identified 11 randomised trials enrolling 735 people taking magnesium to prevent skeletal muscle cramps. In older adults with idiopathic (mostly nocturnal) leg cramps, magnesium was no better than placebo: the change in cramps per week at four weeks was -9.59% (95% CI -23.14% to 3.97%, 3 studies, 177 participants, moderate certainty) and the absolute difference was -0.18 cramps per week (95% CI -0.84 to 0.49, 5 studies, 307 participants), with no difference in the proportion achieving a 25% reduction (RR 1.04, 95% CI 0.84 to 1.29, high certainty) nor in cramp intensity or duration. Evidence in pregnancy-associated cramps was conflicting and could not be pooled. Major adverse events did not differ, but minor mostly gastrointestinal effects were more common on magnesium (RR 1.51, 95% CI 0.98 to 2.33).
Conclusions
It is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps.
Limitations
All five pregnancy trials and the single cirrhosis trial were at high risk of bias and could not be pooled; no randomised trials at all exist for exercise-associated or disease-associated cramps, so the confident null applies only to older adults with idiopathic cramps.
Supplements Studied
It is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps.
Related Health Concerns
Study Details
Access Study
This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.