Ostarine is a selective androgen receptor modulator (SARM) that is designed to have similar effects to testosterone, used to increase muscle mass and strength, as well as to decrease body fat. It is often researched for potential therapeutic applications in muscle wasting diseases and osteoporosis, although it is not legally approved for human use by regulatory bodies like the FDA. Ostarine is also popular among bodybuilders and athletes for performance enhancement, despite being banned by WADA and other sports organizations.