What causes muscle cramps?

    Written by:
    Peter Woznik

    Fact-checked

    by:

    Louie Neri, Jeremy A. Alland
    Last Updated: May 16, 2025

    The exact cause of muscle cramps is not well understood, but dehydration, electrolyte imbalances, muscle fatigue, and nerve dysfunction are potential factors. Additionally, rare causes such as certain medications and specific diseases may also contribute to muscle cramps and warrant examination by a healthcare professional.

    The underlying cause of muscle cramps is not well understood.[1] [1] Much of the evidence is nonscientific or observational.[2]

    One hypothesis for the cause of muscle cramps is because of dehydration and/or electrolyte abnormalities. However, trials have shown no significant correlations between hydration, serum electrolyte levels, and muscle cramps.[3][4]

    A stronger hypothesis may be muscle fatigue and nerve dysfunction, and would help to explain why muscle cramps can occur after changes to exercise (e.g., unusually high volume or intensity, or unusual heat or humidity in the environment).[4]PMID:33998664]

    The cause may ultimately be multifactorial. People with muscle cramps should be examined by a licensed healthcare professional to explore the above potential causes, along with more rare causes of muscle cramps, such as:[5]

    • Drugs (e.g., nifedipine, cimetidine, terbutaline, salbutamol, clofibrate, penicillamine, diuretics, ethanol)[5]
    • Liver diseases, such as cirrhosis
    • Neurological diseases, such as Charcot-Marie-Tooth disease[1][6]