MSM (methyl-sulfonyl-methane) is a natural sulfur, most abundant in our body after water ans sodium. However, it should not be confused with sulfur drugs or dimethyl sulfoxide (DMSO), to which some people are allergic. It originates as dimethyl sulfide (DMS) in the ocean with an aid of plankton, . . . → Read More: MSM (Methylsulfonylmethane).