Ostarine (MK-2866/Enobosarm, SARM)

Tier 4 — risky / avoid · Liver damage · Hormonal suppression · Banned

The most commonly sold SARM, marketed for muscle growth and fat loss. Failed to meet endpoints in phase III clinical trials for muscle wasting. Causes dose-dependent testosterone suppression, liver enzyme elevation, and lipid disruption. Banned by WADA and found as an undeclared adulterant in many "legal" supplements. FDA has issued multiple warning letters to companies selling ostarine.

Dose: AVOID — failed clinical development; causes hormonal suppression and liver damage; banned by WADA