Myths vs facts: Magnesium and Sport

Magnesium is frequently marketed as a cure for muscle cramps and a performance enhancer in sports. The evidence tells a more nuanced story. Magnesium is indeed critical for muscle contraction, nerve function, and energy metabolism. Deficiency can contribute to cramps, but in well-nourished athletes, supplementation rarely provides measurable benefits. Randomized controlled trials show that magnesium supplementation does not consistently prevent exercise-associated cramps or improve strength or endurance in individuals with normal magnesium status. Any performance gain is limited to those with confirmed deficiency, which is uncommon among athletes without specific risk factors (e.g., heavy sweating, low dietary intake, certain medications). Furthermore, high-dose magnesium can cause gastrointestinal side effects like diarrhea. Genetic variants in magnesium transporters (e.g., TRPM6) are not covered in the provided context and lack validated clinical utility for sports. The bottom line: magnesium is essential but not a sports miracle. A balanced diet typically meets needs; supplementation is only indicated when deficiency is diagnosed. Evidence: mostly mechanistic and observational; large-scale RCTs are lacking.