Best MSM supplies highly purified MSM (methylsulfonylmethane) a compound notable for its methyl groups (required for numerous metabolic functions) and the conditionally essential mineral sulfur which is a crucial component of powerful antioxidants such as N-acetylcysteine and glutathione. Although MSM occurs naturally in some foods and in the human body at low concentrations a significant amount of MSM is lost during the heating and processing of foods. *