MSM - Methylsulfonylmethane is an organic sulfur compound that occurs naturally in dogs. MSM is part of the process that increases the permeability of the cell wall, which simplifies the cell's removal of waste products, provides effective nutrient absorption while improving circulation and oxygen absorption. This, in turn, can lead to a shift in the lactic acid threshold. MSM can act as an antioxidant and reduce the amount of free radicals after physical exertion, which in return can improve the dog's recovery.