SR9009 is usually classified for simplicity as SARM (Selective Modulators of the Androgen Receptor), although it is actually an agonist of REV-ERB. REV-ERB is a protein found mainly in adipose tissue, liver, muscle and brain. It affects the circadian rhythm of these tissues, commonly known as the "biological clock. This rhythm is defined as a series of patterns occurring in our body during each day. SR9009 was created to combat sarcopenia, the age-related destruction of skeletal muscle by the body.