Does magnesium help leg cramps, or should the cause be assessed?
Evidence does not support routine magnesium for every muscle cramp, and benefit in pregnancy-related cramps remains uncertain. Confirmed deficiency may need replacement, but a cramp alone does not prove it. Supplements can cause digestive effects and interactions, with added risk in kidney impairment.
Details
What studies show
A Cochrane review found clinically meaningful prevention of typical cramps in older adults unlikely, while pregnancy studies were conflicting. Advertising or one person’s experience does not show that the same dose will help everyone.
Review the cause
Record the timing, duration and relationship to exercise and medicines. A clinician can distinguish cramps from nerve pain or circulation problems and request tests when indicated. Do not stop prescribed treatment or assume a particular mineral deficiency without assessment.
Before buying a supplement
Discuss the amount of elemental magnesium and interactions with antibiotics or other medicines, and avoid combining multiple products. Diarrhoea can occur, and impaired kidneys increase the risk of accumulation. Leg pain with new swelling or increasing weakness needs examination rather than simply trying a supplement. Pregnancy-related symptoms also deserve individual advice.
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