Sulfur seems to be important in the strength and maintenance of joint tissue, especially cartilage. Since sulfur is a significant component of MSM, one possible benefit of MSM is in the treatment of joint problems such as sports injuries, osteoarthritis and tendinitis. MSM also seems to help reduce inflammation [source: MSM Guide].
Many people with joint injuries or early signs of osteoarthritis take supplements such as glucosamine sulfate or chondroitin in an effort to stave off further joint damage [source: Shiel]. Although its benefits have not been proven, you might also be able to use MSM this way -- either as a supplement or as a topical gel on the skin of the affected joint [sources: Mayo Clinic, MSM Guide].
It's important to note that MSM is not an acute pain remedy. Patients and doctors alike hope that MSM helps the body's own repair and maintenance systems work better -- but if you've just sprained your ankle, you should be reaching for the ibuprofen, not the MSM.
There are a few indications that MSM may help with certain respiratory conditions, such as asthma, seasonal allergies and snoring. But clinical proof is slim. Many more studies are needed to establish whether MSM has true medical benefits, and if so, what they are [sources: Lang, Mayo Clinic].
At least one doctor notes that, while the body does need sulfur -- which is an essential mineral -- supplemental MSM may not be the best way to get it. Dietary sulfur comes from the digestion of protein-rich foods (meat and dairy products, legumes, eggs and nuts), so you may be getting enough from whatever source of protein you choose to eat [source: Lang].
The nutritional-supplement industry touts MSM as a muscle-builder and a hair-grower. We'll explore those claims in more detail later.
Even if the claims of MSM's effectiveness need more proof, it might be tempting to take the supplement anyway, just in case it does work. Can MSM ever hurt you? Read on.