Methylsulfonylmethane, commonly known as MSM, is a metabolite of DMSO (Dimethyl Sulfoxide). Found in nature, MSM has been used as a carrier for various compounds. MSM is an odorless, virtually tasteless, white crystalline substance often used for joint support and improved blood circulation. MSM (99%). Bio-Available Sulfur-Maximum Effectiveness. Quick Assimilation. MSM 4 LB (184 Day Supply).