Magnesium for skeletal muscle cramps

Area of Science:

• Neurology
• Nutritional Science
• Evidence-Based Medicine

Background:

• Skeletal muscle cramps are common, often idiopathic, and associated with pregnancy, aging, exercise, or neurological disorders.
• Magnesium supplements are marketed for cramp prevention, but their efficacy is not well-established.
• This Cochrane Review updates previous findings by incorporating recent studies on magnesium for cramp prophylaxis.

Purpose of the Study:

• To assess the effectiveness of magnesium supplementation versus placebo, no treatment, or other therapies for skeletal muscle cramps.
• To evaluate magnesium's impact on cramp frequency, intensity, and duration across various patient groups.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating oral or intravenous magnesium for cramp prevention.
• Searched multiple databases including Cochrane Neuromuscular, CENTRAL, MEDLINE, Embase, and ClinicalTrials.gov.
• Assessed risk of bias and extracted participant-level data where available.

Main Results:

• For idiopathic cramps in older adults, magnesium showed no statistically significant difference in cramp frequency, intensity, or duration compared to placebo (moderate to high-certainty evidence).
• Evidence for pregnancy-associated leg cramps was conflicting, with one study showing no benefit and others yielding inconsistent results.
• Minor adverse events, primarily gastrointestinal issues like diarrhea, were more frequent in the magnesium group (low-certainty evidence).

Conclusions:

• Magnesium supplementation is unlikely to provide clinically meaningful prevention of skeletal muscle cramps in older adults.
• Further research is needed to clarify the efficacy of magnesium for pregnancy-associated rest cramps due to conflicting evidence.
• No RCTs were identified for exercise-associated or disease-specific cramps (e.g., ALS), except for an inconclusive study in liver cirrhosis patients.