Rankings / Muscle & Strength

Ostarine (MK-2866 / enobosarm)

Muscle & Strength · SARM

Tier C+

Reviewed by Read Off Label · Last reviewed · How we grade

anabolicbannedresearch-only
5.5 / 10
Tier C+
Ev 6 Bn 5 Sf 5

Bottom line

Read Off Label grades Ostarine (MK-2866 / enobosarm) as C+ (5.5/10) based on moderate evidence, med benefit magnitude, and a med-risk safety profile.

Most studied SARM clinically.

Studied, labeled, or reported-use context: Typical illicit: 10-25 mg/day PO for 8-12 weeks — NOT FDA-approved; sold as 'research chemical' on the gray market; banned in sport (WADA S1). Simultaneously in legitimate Phase 2 development by Veru Inc. — see Notes; not individualized guidance.

What the evidence says

Most studied SARM clinically. Veru ARES Ph3 in AR+/ER+ breast cancer (2024). FDA has warned against SARMs in supplements multiple times. 2025 Grassley/Whitehouse SARMs Control Act bill introduced again; previous versions (2018, 2019) did not pass. Despite marketing, not 'side-effect-free' vs steroids. Veru has pivoted enobosarm to preserving lean mass during GLP-1 (semaglutide) weight loss - Phase 2b QUALITY in older adults; FDA alignment reached Sept 2025 for enobosarm + GLP-1 RA in obesity. The earlier muscle-wasting/cachexia program was discontinued (improved lean mass but not strength), making the 'keep the muscle on GLP-1' use its most credible clinical path. **Dual status, confirmed 2026-08-29 — this is the row where the gray market and legitimate drug development are running in parallel on the same molecule.** Under the name **enobosarm**, Veru Inc. is developing it specifically to **preserve muscle during GLP-1 weight loss**, which is one of the most-discussed problems for this audience. A Phase 2 dose-finding study of enobosarm plus semaglutide in muscle loss and obesity (NCT06282458, n=168) completed its primary endpoint in April 2025, and a Phase 2b proof-of-concept trial, **PLATEAU** (NCT07446998, n=200, enobosarm plus Wegovy, endpoints covering total body weight, physical function and HOMA-IR), is currently **recruiting** with primary completion estimated October 2027. Note the earlier history is not a clean run: the Phase 3 breast-cancer programme was terminated or withdrawn across several trials in 2024. **None of this makes gray-market ostarine safe or legal** — the product sold online is unapproved, frequently mislabelled, and banned in sport. It does mean the underlying compound is being tested properly for an indication readers care about, and that a real answer is roughly a year away. Citation repair 2026-08-29: the FDA SARMs consumer-update URL 404s. Replaced with the current FDA warning page on SARM use among teens and young adults, which carries the same position and a fuller harm list — heart attack and stroke risk, psychosis, liver injury and acute liver failure, infertility, miscarriage and testicular shrinkage.

Mechanism

Selective androgen receptor modulator; tissue-selective AR agonist (muscle/bone agonist, lesser prostate activity); developed by GTx for muscle wasting and now Veru for breast cancer (ARES trial)

Studied, labeled, or reported dose & route

Typical illicit: 10-25 mg/day PO for 8-12 weeks

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

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Common questions

What does the evidence show about Ostarine (MK-2866 / enobosarm)'s effects?
Read Off Label rates the evidence for Ostarine (MK-2866 / enobosarm) as Moderate and the benefit magnitude as med, producing an overall grade of C+ (5.5/10). Most studied SARM clinically.
What safety findings are reported for Ostarine (MK-2866 / enobosarm)?
Ostarine (MK-2866 / enobosarm) has a med risk profile in the database. Med (HPG suppression dose-dependent; LFT elevations; reported heart-attack cases in young users — FDA warning 2017) Legal status: NOT FDA-approved; sold as 'research chemical' on the gray market; banned in sport (WADA S1). Simultaneously in legitimate Phase 2 development by Veru Inc. — see Notes.
What doses or routes are reported for Ostarine (MK-2866 / enobosarm)?
Typical illicit: 10-25 mg/day PO for 8-12 weeks This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Ostarine (MK-2866 / enobosarm) work?
Selective androgen receptor modulator; tissue-selective AR agonist (muscle/bone agonist, lesser prostate activity); developed by GTx for muscle wasting and now Veru for breast cancer (ARES trial)

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.