Retatrutide remains investigational.
AJ Pakpour's independent evidence review synthesizes Phase 2 and Phase 3 clinical data, regulatory developments, and the American gray market for retatrutide. 120 references. Research cutoff September 30, 2026.
Eli Lilly announced May 21, 2026 topline Phase 3 results for TRIUMPH-1. The 12 mg dose arm achieved 28.3% mean body weight reduction at 80 weeks; 9 mg achieved 25.9%; 4 mg achieved 19.0%. A prespecified extension population with baseline BMI ≥35 showed up to 30.3% at 104 weeks. These are topline results; peer-reviewed publication is pending.
The Phase 2 NEJM-published trial (Jastreboff et al., 2023) demonstrated dose-dependent weight reduction of up to 24.2% at 48 weeks in adults with obesity. This is the primary peer-reviewed efficacy dataset for retatrutide.
Retatrutide remains an investigational drug with no FDA approval as of September 2026. Eli Lilly has announced plans for a Q1 2027 regulatory submission. Compounded formulations are not FDA-approved equivalents.
Following TRIUMPH-1 topline results, Eli Lilly announced plans to submit a regulatory application to the FDA in Q1 2027. FDA approval and commercial availability are not guaranteed and depend on the full regulatory review process.
