andarine

Andarine, also known by its developmental code S-4, is a selective androgen receptor modulator (SARM) that was developed for potential treatment of muscle wasting, osteoporosis, and age-related sarcopenia. It binds to the androgen receptor and is intended to act as a tissue-selective agonist to promote anabolic effects in muscle and bone while reducing androgenic effects in non-skeletal tissues such as the prostate.

In pharmacology, SARMs like Andarine aim to separate anabolic and androgenic effects of testosterone. Andarine has shown relatively high affinity for the androgen receptor and demonstrated preferential activity in muscle and bone in preclinical studies, but the degree of tissue selectivity is dose-dependent and not absolute. The practical outcome of this selectivity in humans has been inconsistent, and effects can vary with dose and duration of exposure.

Clinical development progressed in the 2010s, with early trials reporting increases in lean body mass and some improvements in bone density. Development was halted due to safety concerns, most notably visual disturbances such as changes in color vision and diminished night vision reported by healthy volunteers at higher doses. Additional concerns about suppression of endogenous testosterone at longer-term use contributed to the decision to discontinue pursuing Andarine clinically.

Andarine is not approved for medical use and is not marketed as a prescription drug. It is listed as a prohibited substance by the World Anti-Doping Agency and is available primarily as a research chemical. Long-term safety remains uncertain, and potential adverse effects include hormonal suppression and, at some doses, risks to liver function.