MSM is an acronym for MethylSulfonylMethane. MSM is essentially a sulphur supplement that provides the body with a bioavailable source of the naturally occurring element sulphur.
Sulphur is an most abundant element within the body and it's estimated that around 0.25% of our body weight (for a 70KG male that's around 1700 grams) at any given time is from the element sulphur. Sulphur has a variety of biological roles in the body and in particular is required to maintain cartilage and supports joint function. Sulphur is a key constituent of hair, nail and skin cells.
NOW Foods MSM contains 34% elemental sulphur by weight. NOW MSM supplements are sourced from dimethyl sulfide (DMS) which is sourced naturally from pine trees.