Best msm 1500 mg supplies pure crystalline msm (methylsulfonylmethane). msm is a naturally-occurring source of organic sulfur that is easily absorbed and used by the body. taken up from the soil by plants, msm found in foods is largely lost during food processing, storage and cooking. msm supports organ and joint function by donating sulfur for maintenance of healthy connective tissue. msm helps keep skin, hair and nails healthy by donating sulfur for production of keratin, a fibrous protein. supports joints function.