Magnesium and Muscle Cramps: Evaluating Clinical Efficacy by Form, Dose, and Patient Group

Abstract Summary

Objective

To evaluate the effectiveness of magnesium supplementation in preventing and reducing skeletal muscle cramps and spasms.

Context

Magnesium is a micronutrient and intracellular cation responsible for biochemical reactions involved in energy production, neuronal activity, and muscle contraction. Magnesium deficiency is associated with neuronal excitability and enhanced neuromuscular transmission, leading researchers to propose a beneficial role for supplementation in muscle cramps—a condition affecting up to 60% of adults.

Methods Used

Approach

Researchers conducted randomized controlled trials of magnesium supplementation in any form to prevent skeletal muscle cramps across any patient group, comparing magnesium against placebo, no treatment, or other therapy.

Data Collection

The primary outcome was cramp frequency measured as percent change from baseline in weekly cramp count at 4 and 12 weeks, alongside cramp intensity rated on a three-point scale and rates of treatment withdrawal due to adverse events.

Researchers' Summary of Findings

Magnesium supplementation is unlikely to provide clinically meaningful cramp prophylaxis for idiopathic skeletal muscle cramps in older adults at any dosage, supported by moderate-certainty evidence. In pregnant women, evidence suggests a possible small benefit, though findings remain weak due to small sample sizes and short follow-up periods. For active individuals, a 2024 systematic review found that magnesium supplementation decreased muscle soreness, improved performance, and had a protective effect on muscle damage. Across all groups, magnesium citrate, glycinate, and lactate demonstrated superior absorption compared to magnesium oxide, the form most commonly available over the counter.

DOI

10.1002/14651858.CD009402.pub3