According to WebMD, methyl sulfonyl methane is a naturally occurring chemical often found in plants and is comprised of large quantities of sulfur, which is thought to treat pain related to arthritis, bursitis and osteoporosis. MSM can be applied topically in the form of a cream or taken orally as a supplement. MSM isn't a required part of the human diet. WebMD says MSM is considered possibly safe.
WebMD lists additional uses for MSM as treatment for tendonitis, scleroderma, muscle cramps, hair loss, scar tissue, periodontal disease, stretch marks, wrinkles and eye inflammation. It's also claimed that MSM may relieve symptoms related to premenstrual syndrome, poor circulation, Alzheimer's disease, allergies, chronic constipation, high cholesterol, diverticulosis, emphysema, type 2 diabetes, migraine headaches, yeast infections, hangovers, radiation poisoning and pneumonia. None of these claims have been scientifically substantiated, although there's slight evidence suggesting MSM may effectively treat hemorrhoids, osteoarthritis, rosacea and exercise-induced stress. People should be safe when taking MSM orally for three months or less. WebMD recommends that people combine topical MSM application with other substances, such as silymarin, hyaluronic acid or tea-tree oil. MSM shouldn't be used topically for more than 20 days. Possible side effects include insomnia, bloating, nausea, itching, diarrhea and headaches.