MSM, methylsulfonylmethane (METH-Yl-sul-FON-il-METH-ane) also known as dimethyl sulfone (DMSO2) and methyl sulfone, is an organic sulfur-containing compound important for optimal health. MSM is made up of 34% sulfurthe fourth most abundant mineral in the human body. Sulfur is a core chemical element necessary for biochemical functioning and an elemental macronutrient for all organisms. Sulfur is also a vital building block of amino acids and connective tissue including joints, cartilage, skin, hair, and nails. MSM also provides methyl groups, which support many essential metabolic processes in the body.