Dimethyl sulfone (DMSO2) is an organosulfur compound with the formula (CH3)2SO2. It is also known by several other names including methyl sulfone and (especially in alternative medicine) methylsulfonylmethane (MSM). This colorless solid features the sulfonyl functional group and is the simplest of the sulfones. It is relatively inert chemically and is able to resist decomposition at elevated temperatures. It occurs naturally in some primitive plants, is present in small amounts in many foods and beverages, and is marketed (under the MSM name) as a dietary supplement. It is sometimes used as a cutting agent for illicitly manufactured methamphetamine. It is also commonly found in the atmosphere above marine areas, where it is used as a carbon source by the airborne bacteria Afipia. Oxidation of dimethyl sulfoxide produces the sulfone, both under laboratory conditions and metabolically. Use as a solvent Because of its polarity and thermal stability, DMSO2 has been used industrially as a high-temperature solvent. For example, displacement of aryl chlorides by potassium fluoride has been conducted in the liquid. With a pKa of 31, the sulfone can be deprotonated with sodium amide. The conjugate base has been used as a nucleophile. Pharmacology and toxicity Nuclear magnetic resonance (NMR) studies have demonstrated that oral doses of MSM are absorbed into the blood and cross the blood/brain barrier. An NMR study has also found detectable levels of MSM normally present in the blood and cerebrospinal fluid, suggesting that it derives from dietary sources, intestinal bacterial metabolism, and the body's endogenous methanethiol metabolism. Medical and dietary use Although no medical uses for MSM have been approved, a variety of health benefits have been claimed and studied. Stanley W. Jacob reported having administered MSM to over 18,000 patients with a variety of ailments; he co-authored a book promoting MSM with a variety of claims, including a utility as a natural source of "biologically active sulfur," suggesting that people are deficient in such forms of sulfur in their dietary intake. There is no Dietary Reference Intake (DRI) or Daily Value established for sulfur but notable dietary sources include cruciferous vegetables, garlic, onions, asafoetida, legumes, nuts, seeds, plant milk, animal milk and eggs (whites and yolks). The claims for the need for sulfur supplementation originate with Robert Herschler, a biochemist who patented "Dietary and pharmaceutical uses of methylsulfonylmethane and compositions comprising it" in 1982. He claimed that MSM was useful in stress, mucous-membrane inflammation, allergies