Methylsulfonylmethane (MSM) is a form of sulfur that is found naturally in the body. MSM contains a natural occurring sulfur called sulfonyl. Unlike the bad sulfur such as sulfites, sulfonyl is important for muscle, joint and bone health. Studies have shown that MSM may improve joint flexibility, reduces swelling, scar tissue and inflammation. According to Earl L. Mindell, Ph. D., MSM softens the cell walls and allows any free radicals to be moved out of the system.