Andarine (S-4) is an selective androgen receptor modulator (SARM) for treatment of conditions such as muscle wasting, osteoporosis and benign prostatic hypertrophy. Compared to testosterone and other anabolic steroids and pro hormones, the advantage of SARMs such as S-4 is that they do not have androgenic activity in non-skeletal-muscle tissues. S4 was designed for treatment of conditions such as muscle wasting, osteoporosis and benign prostatic hypertrophy, using the non-steroidal androgen antagonist bicalutamide as a lead compound.