Enobosarm
Enobosarm (ostarine, GTx-024, MK-2866)
Also known as: Ostarine, GTx-024, MK-2866
The selective androgen receptor modulator known on the gray market as ostarine, now in formal trials where 3 mg cut lean-mass loss on semaglutide by 71% in adults over 60.
Overview
Enobosarm activates the androgen receptor selectively in muscle and bone. It failed earlier programs in cancer cachexia and is widely misused as an unapproved SARM. Veru's QUALITY Phase 2b combined it with semaglutide in adults aged 60 and older: over 16 weeks lean-mass loss fell from 4.1% to 1.2%, 54.5% fewer participants had a 10% or greater decline in stair-climb power, and gastrointestinal side effects were fewer. A 3 mg dose was chosen for Phase 3 and a maintenance study is enrolling.
Mechanism of action
Tissue-selective androgen receptor agonism that promotes muscle protein synthesis with less androgenic effect on prostate and skin than testosterone.
Key studies & citations
- Human2025
Veru reports positive safety and efficacy results from Phase 2b QUALITY study
71% less lean-mass loss with semaglutide in adults 60 and older.
Veru press release - Human2026
Veru enrolls first patient in Phase 2b PLATEAU maintenance study
Tests enobosarm after GLP-1 discontinuation.
Veru press release - Human2013
Enobosarm in cancer cachexia (POWER trials)
Earlier trials showed lean-mass gains but mixed functional outcomes.
The Lancet Oncology
Frequently asked questions
Is ostarine the same as enobosarm?
Yes. Ostarine is the common name for the same molecule sold illicitly; the trial drug is a pharmaceutical-grade version at defined doses.
Is it safe?
Gray-market SARM products have been linked to liver injury and hormonal suppression, and they are often mislabeled. The trials use 3 mg with monitoring; that says nothing about unregulated products.