What is MSM? MSM, short for methylsulfonylmethane, is an organic form of sulfur readily absorbed and utilized by our bodies. MSM is composed of 34% bio-available sulfur, making it the richest source of organic sulfur available. MSM is a safe, natural, assimilable food, which assists the body in maintaining adequate sulfur stores. MSM may support the body in regulating insulin production, improving skin smoothness and elasticity, regulating environmental and allergic sensitivities, enhancing bowel function and liver detoxification, and enhancing respiratory function.