[Jaapie]

MSM (methylsulfonylmethane, dimethyl sulfone, DMSO2) is a naturally occuring thiol compound and one of the more popular dietary supplements. It is 34% elemental sulfur and has a metabolic relationship with methionine, and is found in small amounts in the diet in sources including milk, grains, meat, eggs, fish, fruit, tea, coffee, and raw vegetables [2-3]. MSM is a metabolite of dimethyl sulfoxide (DMSO), a compound that has been researched for a wide range of therapeutic purposes. About 17% of orally administered DMSO metabolizes into MSM [1], and the two compounds have many related properties. DMSO inhibits certain aspects of the inflammatory response, and preliminary evidence suggests that MSM shares this property [1]. However, MSM may pose a few advantages, as it does not metabolize into the volatile compound dimethyl sulfide as DMSO does, and also does not cause the garlic-like body odor associated with DMSO use [1-2].

There are many claims made for MSM supplements, including relief of pain, inflammation, arthritis, allergies, parasitic infections, asthma, constipation, hyperacidity, emphysema, carpal tunnel, acne, fibromyalgia and memory loss [2-4]. There are few studies to support most of the claims for MSM supplements, and even less information in peer-reviewed journals. The two uses with solid scientific evidence are treatment of arthritis and interstitial cystitis [2, 4]. A preliminary study assessed the effect of 2,250 mg of MSM on ten arthritis patients compared to six treated with placebo. Eight of the MSM-treated patients had pain relief within six weeks, compared to minimal improvement in one in the placebo group [2]. Although this study is promising, it should be followed by further studies before a conclusive relationship is assumed. A 30-day open trial with 30 subjects indicated that 2600 mg MSM provided relief from the symptoms of seasonal allergic rhinitis (SAR), which affects over 23 million Americans [1]. However, not only was this an open trial, it was funded by a company that sells MSM, and it has been pointed out that it omitted some important data such as measures of symptom severity [5]. In other studies, MSM has been reported to improve drug sensitivity to aspirin, oral antibiotics, and NSAIDS; prevent round worm, Giardia, and Trichomonas infections by competing for binding sites at the mucus membrane; and speed the treatment of athletic injuries and reduce the duration of and need for chiropractic visits [2]. Although most of these studies were arguably biased or had design flaws, there are still a number of possible promising roles for MSM supplementation.

There have also been a few animal studies with MSM. In genetically susceptible mice, it was effective in preventing autoimmune disease and inflammatory joint disease, and in other studies it delayed the onset of colon cancer and mammary cancer [2]. These studies may lend some further credence to the existing human data.

It is important to note that although the evidence for the claims made for MSM is still weak, it is an extremely safe supplement. A toxicological study in rats found no adverse effects from 2 g/kg acutely or 1.5 g/kg for 90 days; this is about the equivalent of six times the maximum recommended human dose [3]. Toxicity has not been reported in animal studies, adverse effects have not been noted in human studies, and long-term users of 2 g or more daily have reported no ill effects [2]. However, there is one concern. MSM has been detected in the brains of humans taking MSM supplements, where it is not normally detectable [3]. This was not associated with changes in the concentrations of important cerebral metabolites, and this combined with the animal data would indicate that it is unlikely that MSM has any important effect on the brain [4].

The recommended dosage for MSM is in the range of 1-6 grams daily, although some physicians have recommended up to 20 grams daily [3]. A study in 1975 indicated that MSM recovery after oral administration was only 3%, suggesting utilization or modification in the gut or liver [3]. This may be why a high dose is needed, but it is also noteworthy that the presence of detectable MSM in the brain after supplementation would indicate that a supplement is enough to significantly increase plasma levels of the compound. Given the present information, it can be concluded that MSM is a safe supplement that may be effective for a variety of purposes, primarily the reduction of pain and inflammation, but further studies are needed to prove efficacy.