Published Research is Minuscule
Medline searches for "methylsulfonylmethane, "MSM," and "dimethylsulfone" found few reports on MSM published in mainstream scientific journals between 1966 and 2000 and none in which MSM was tested for effectiveness against any human ailment. Two studies in rats found that MSM delayed the onset of chemically induced cancers [9,10]. However, since no further studies have been reported in more than 10 years, this appears not to have been a fruitful line of research. Another study found no effect on the onset of diabetes in rats [11].
The claim that MSM is an important source of dietary sulfur is unsupported by published research. One study that involved feeding MSM to guinea pigs found that the sulfur from MSM was absorbed rapidly into the blood stream and was incorporated into methionine and cysteine of serum proteins. However, most of the sulfur appeared in the urine; less than 1% was incorporated into serum proteins. Increasing the dosage of MSM 100-fold increased the incorporation into serum proteins only 3-fold, indicating that the capacity to use MSM in this pathway is limited [12]. Thus, while MSM is naturally present in small amounts in a variety of foods, its contribution to sulfur metabolism in humans is likely to be negligible.
Regulatory Action
Karl Loren (whose birth name was Loren Karl Troescher) operates what he calls "The Largest Web Presence For MSM On The Planet," a site that markets MSM products with many health claims and testimonials for them. In October 2000, the FDA warned him that the long list of therapeutic claims he was making for these products made them drugs would be illegal to market without FDA approval. The letter stated that the FDA had seen no evidence that the products were safe and effective for their intended uses [13].
The Bottom Line
No published research studies link MSM to any of the health claims made by its marketers. Sulfur needed in human metabolism comes from dietary protein. MSM supplements probably make little or no contribution to the body's sulfur requirements. Thus there is no good reason to use MSM supplements.