Methylsulfonylmethane (MSM) is a sulfur-containing compound commonly used as a dietary supplement for joint and muscle health. Scientific evidence supporting its use for the muscle system is limited, but some studies suggest potential benefits. MSM is thought to reduce inflammation, oxidative stress, and muscle soreness, which could theoretically aid in muscle recovery after exercise.

Several small clinical trials have examined the effects of MSM on exercise-induced muscle damage and recovery. For example, a double-blind, placebo-controlled study published in the "Journal of Sports Medicine and Physical Fitness" (2012) found that MSM supplementation (3g daily for 1 month) reduced muscle soreness and fatigue in healthy men following strenuous exercise. Another randomized controlled trial in the "Journal of the International Society of Sports Nutrition" (2014) reported that MSM supplementation (3g daily for 2 weeks) led to reductions in markers of muscle damage and oxidative stress after running.

However, these studies are generally small, of short duration, and have methodological limitations. Reviews and meta-analyses note that while MSM appears safe and may modestly reduce muscle soreness and damage, the overall quality and quantity of evidence is not strong. There is insufficient data to conclusively recommend MSM for muscle support, but it is used for this purpose based on preliminary scientific findings rather than historical or traditional use.