Retatrutide Phase 3 Results: 24% Weight Loss Tops FDA Approval Track (2026 Update)

Retatrutide Status (February 2026)

Currently in Phase 3 Trials. Following the Dec 11, 2025, TRIUMPH-4 success (28.7% weight loss), Eli Lilly is expected to file for FDA approval in late 2026.

Current FDA Status: Investigational (Phase 3)

As of January 2026, Retatrutide is not yet FDA-approved for public sale. It is currently in the final stages of the TRIUMPH Phase 3 clinical trial program.

However, the landscape changed significantly on December 11, 2025, when Eli Lilly released the first "topline" results from the TRIUMPH-4 study. These results were record-breaking and have accelerated the timeline for potential 2026-2027 availability.

The December 2025 Breakthrough: TRIUMPH-4 Results

The TRIUMPH-4 trial focused on adults with obesity and knee osteoarthritis. The results, published in late 2025, confirmed that Retatrutide is significantly more potent than both Wegovy (Semaglutide) and Zepbound (Tirzepatide).

  • Average Weight Loss: Patients on the 12mg dose lost an average of 28.7% of their body weight (approx. 71.2 lbs) over 68 weeks.
  • Osteoarthritis Relief: Over 75% reduction in knee pain scores, with 1 in 8 patients becoming entirely pain-free.
  • Metabolic Markers: Massive improvements in blood pressure (-14.0 mmHg) and cardiovascular risk markers.
  • Cardiometabolic Boost: Trial data showed a 14.0 mmHg reduction in systolic blood pressure and significant improvements in non-HDL cholesterol and triglycerides.
  • Market Outlook: With 7 additional Phase 3 trials scheduled to read out in 2026, Retatrutide is currently the highest-efficacy "triple agonist" molecule in development.

When will Retatrutide be available? (2026-2027 Timeline)

Eli Lilly currently has seven more Phase 3 trials (TRIUMPH-1 through TRIUMPH-3 and others) scheduled to wrap up throughout 2026.

  1. Late 2026: If the remaining trials are successful, Eli Lilly is expected to submit a New Drug Application (NDA) to the FDA.
  2. Early 2027: Under standard review timelines (6–10 months), the FDA could grant approval by the first or second quarter of 2027.

Retatrutide FDA Timeline Update

Phase 3 trials are expected to conclude in May 2026, with a projected FDA decision in early 2027.
Read our Full 2026–2028 Roadmap Here →

Safety & New Side Effects (Dysesthesia)

While the weight loss is unprecedented, the December 2025 data highlighted a new safety signal called dysesthesia. Approximately 20.9% of patients on the highest dose reported skin sensitivity, tingling, or tenderness to the touch. While generally mild, this is a unique side effect that distinguishes Retatrutide from previous GLP-1 medications.

Answers to Commons Questions About Retatrutide

Is Retatrutide FDA approved as of January 2026?

No, Retatrutide is not yet FDA approved. It is currently an investigational drug in the final Phase 3 clinical trials (the TRIUMPH program). While the first Phase 3 results (TRIUMPH-4) were released in December 2025, official FDA approval is not expected until late 2026 or 2027.

How much weight loss did Retatrutide show in Phase 3 trials?

In the TRIUMPH-4 Phase 3 trial results released on December 11, 2025, participants on the maximum 12mg dose lost an average of 28.7% of their body weight (approximately 71.2 lbs) over 68 weeks. This surpasses the results seen in earlier trials for both Wegovy and Zepbound.

What is the current projected release date for Retatrutide?

Retatrutide is projected to be ready for launch in 2027 or early 2028, depending on the completion of the remaining seven Phase 3 trials. The TRIUMPH program is expected to yield several more data readouts throughout 2026.

What new side effects were discovered in the December 2025 data?

The Phase 3 TRIUMPH-4 trial identified a new safety signal called dysesthesia (an abnormal or sensitive sense of touch), which occurred in 20.9% of participants at the 12mg dose. Other common side effects include nausea (43%), diarrhea (33%), and vomiting (21%). Read our full side effects guide here.

Can I buy Retatrutide or get it prescribed right now?

No, Retatrutide cannot be legally prescribed or dispensed in the U.S. outside of authorized clinical trials. The FDA and medical experts strongly caution against purchasing "research" versions online, as these are unregulated and potentially unsafe. Read more about buying Retatrutide here.