Sulfur (MSM) What Is Organic Sulfur (MSM) ? Organic sulfur, commonly known as MSM (methylsulfonylmethane) , is a naturally occurring sulfur compound found in plants, animals, and the human body. Sulfur is the third most abundant mineral in the body and plays a critical role in connective tissue structure, detoxification pathways, and cellular function. MSM is widely used as a dietary supplement to support joints, skin, inflammation balance, and overall wellness. How MSM Works