MSM, or methyl-sulfonyl-methane, is a natural form of sulfur found in all living organisms and presents in our body's fluids and tissues, in milk, fruits, vegetables, and grains. Although MSM occurs naturally in foods, even moderate food processing destroys most of it. Plants, animals and humans need sulfur for a wide variety of biological processes. MSM is a source of biological sulfur, which is a major component in many of the body's proteins, tissues, and enzymes. MSM helps form the bonds that link connective tissue together. MSM benefits the growth and texture of nails and hair, and increase elasticity of the skin.