Methylsulfonylmethane (MSM, dimethyl sulfone, CAS 67-71-0) is a stable, water-soluble sulfone made by oxidizing DMSO. It is the largest downstream derivative of DMSO, consumed mainly as a joint-health supplement, with secondary uses as a high-boiling solvent and chemical intermediate. Both supplement-grade and industrial MSM are outlets for DMSO feedstock.
(CH3)2SO + H2O250–90 °C→(CH3)2SO2 + H2O
Reaction 1: Oxidation of DMSO to methylsulfonylmethane (MSM / dimethyl sulfone)
What MSM Is and How It Is Made
| Property | Value |
|---|---|
| Molecular formula | C₂H₆O₂S |
| CAS number | 67-71-0 |
| Appearance | White crystalline solid |
| Melting point | 109 °C |
| Boiling point | 238 °C |
| Water solubility | Highly soluble |
Table 1: MSM key properties
MSM is manufactured by oxidizing DMSO with hydrogen peroxide at 50–90 °C, raising the sulfoxide sulfur from S(IV) to the fully oxidized S(VI) sulfone, so each kilogram of MSM derives from roughly one kilogram of DMSO feedstock. On cooling, MSM crystallizes from the aqueous phase and is isolated by centrifugation, washing, and drying. The older nitric-acid oxidation route has largely fallen out of use because of higher waste generation and safety concerns.
Where MSM Is Used
The dominant use is in human and animal joint-health supplements, where MSM is generally recognized as safe (GRAS) for dietary use and is sold in tens of thousands of tons annually. It is commonly formulated with glucosamine and chondroitin for osteoarthritis support, marketed as a source of bioavailable sulfur. As a structural analogue of DMSO, MSM carries the same methyl groups bound to a fully oxidized sulfur, but without the strong solvent action.
Industrially, MSM functions as a high-boiling, polar, aprotic solvent for specialty reactions where DMSO’s oxidizing potential is undesirable, and it is a starting material for sulfone and sulfonamide derivatives used in agrochemical and pharmaceutical intermediate synthesis. In skin and hair formulations it acts as a penetration enhancer and anti-inflammatory ingredient, leveraging its structural similarity to DMSO without the strong solvent properties that carry dissolved compounds through the skin barrier.
DMSO Feedstock and Quality
MSM production is more forgiving of DMSO feedstock quality than downstream derivatives that preserve the sulfoxide chemistry, because the oxidation and crystallization steps further purify the product. Industrial or pharma-grade DMSO both feed MSM production, with food-grade processing conditions required for supplement-grade MSM. Residual DMSO and dimethyl sulfide are controlled as process-related impurities under USP general chapters. For a DMSO supplier, the implication is that MSM production accepts a broad grade range but still requires consistent water and dimethyl sulfide control to keep crystallization clean and supplement-grade within specification.
References
- Buttgereit, F.; et al. MSM (dimethyl sulfone) — a review of its biology and clinical applications. Gen. Pharmacol. 1998, 30(2), 159–165.
- U.S. FDA GRAS Notice No. GRN 000068: Methylsulfonylmethane (MSM) as a dietary ingredient.