Methylsulfonylmethane (MSM) is an is an organic sulfur compound. It occurs naturally in some plants and is present in small amounts in many foods and beverages.

MSM provides an important, bioavailable source of dietary sulfur. Sulfur plays a key role in the maintenance of normal body function. It is an essential dietary component responsible for maintaining the conformation of the body's proteins by forming flexible disulfide bonds between certain amino acids and in maintaining the integrity of connective tissue.

MSM is a dietary supplement that is usually used for relief of pain from arthritis, back pain or muscle pain.

 Methylsulfonylmethane (MSM) is often offered in combination with other supplements such as chondroitin sulfate and glucosamine.