MSM (methylsulfonylmethane) is an important source of sulfur. The use of sulfur has been known since ancient times. People enjoyed bathing in sulfur-rich hot springs, often of volcanic origin, to relax their bodies. Today, many spas still contain water rich in sulfur compounds. MSM, also known as dimethylsulfone, is a chemical compound consisting of two methyl groups linked to a sulfur atom. Sulfur is one of the macrominerals, along with calcium, magnesium, potassium, sodium and phosphorus, that the body needs in large quantities every day. Despite its importance, sulfur is one of the most underestimated minerals. Sulfur from MSM is a building block of the sulfur-containing amino acids cysteine and methionine, which are essential for almost all proteins. Scientific interest in MSM is increasing every year, with more than 300 scientific publications to date.