SARM
Ostarine (MK-2866)
SaveThe most extensively studied SARM, developed by GTx Inc. for muscle wasting and osteoporosis. Reached Phase III trials but did not gain FDA approval.
Quick verdict
The best-characterized SARM with Phase III data. Showed lean mass gains but failed to meet primary functional endpoints in pivotal cancer-cachexia trials.
Evidence score
A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.
What the research shows
Phase II trials showed dose-dependent lean mass increases in healthy elderly and cancer patients. Two Phase III trials (POWER 1 & 2) for cancer cachexia met the lean mass co-primary endpoint but missed the stair-climb power endpoint, leading to an FDA Complete Response Letter.
Benefits
- Phase III lean mass data in cancer cachexia
- Oral once-daily dosing
- Most extensive human safety database among SARMs
Dosage notes
Phase II/III trials used 1–3 mg/day. No approved dose.
Side effects
- Testosterone suppression
- Liver enzyme elevations
- Headache
- Back pain
Who should be cautious
Suppresses testosterone dose-dependently. Liver enzyme elevations reported in some users. WADA-banned. Not FDA-approved.
What this page cannot tell you
Lean mass gains did not consistently translate into functional improvements in Phase III. This is the central limitation of current SARM development.
Leaderboard scores
- Muscle50
- Recovery30
Write a review
Sign in to write a review.