RAD140 (Testolone) is a potent oral SARM (Selective Androgen Receptor Modulator) developed by Radius Health, Inc. as a potential future replacement for exogenous testosterone replacement therapy (TRT). Current research on RAD140 focuses on its potential benefits in increasing muscle mass, combating muscle wasting, treating osteoporosis, breast cancer, and protecting brain cells.
RAD140's Affinity for the Androgen Receptor:
RAD140 demonstrates excellent affinity for the androgen receptor (Ki 7 nM compared to 29 nM for testosterone and 10 nM for dihydrotestosterone or DHT), as well as good selectivity for other steroid hormone nuclear receptors. The closest target receptor is the progesterone receptor (IC50 at 750 nM vs 0.2 nM for progesterone). Functional androgen agonist activity was confirmed in vitro in the C2C12 osteoblast differentiation assay, showing an EC50 of 0.1 nM (compared to DHT at 0.05 nM).
RAD140’s high selectivity and strong binding to the androgen receptor make it a promising candidate for various therapeutic applications, especially in muscle and bone health.