Retatrutide Phase 3 TRIUMPH Results
What the 2026 Data Shows
A research-focused breakdown of TRIUMPH-1 weight loss outcomes, TRANSCEND-T2D-1 glycaemic data, and emerging secondary endpoints
Introduction
When Eli Lilly’s Phase 2 retatrutide data landed in the New England Journal of Medicine in 2023, the research community took notice — 24.2% mean weight loss at 48 weeks, with no plateau in sight. The obvious question was: what would Phase 3 look like?
In 2026, we have answers. The TRIUMPH programme has now reported, and the data is substantial.
TRIUMPH-1: Weight Loss Outcomes at 80 Weeks
The headline figure from TRIUMPH-1 is a 28.3% mean body weight reduction at 80 weeks — a meaningful step up from Phase 2, and consistent with the trajectory that hadn’t plateaued at week 48.
- 45.3% of participants lost 30% or more of their body weight — a threshold previously considered exceptional even in surgical weight loss research
- Weight loss continued to progress beyond the Phase 2 timeframe, confirming the earlier signal that plateau had not been reached at 48 weeks
- The trial was conducted in participants with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related comorbidity
For researchers studying energy homeostasis and receptor-mediated metabolic regulation, the sustained trajectory is particularly notable — it suggests the glucagon receptor component continues to drive energy expenditure over extended periods, rather than attenuating as seen with some earlier agents.
TRANSCEND-T2D-1: Glycaemic Outcomes
The TRANSCEND-T2D-1 arm examined retatrutide in participants with type 2 diabetes, where the triple-agonist mechanism has distinct implications given the interplay between GLP-1, GIP, and glucagon signalling in glucose homeostasis.
- HbA1c reductions of up to 1.94% from baseline across the highest dose cohorts
- Reductions were observed across all active dose groups
- Results position retatrutide among the most potent investigational agents for glycaemic modulation currently in Phase 3
Beyond Weight and Glucose: Emerging Secondary Endpoints
The TRIUMPH programme also reported on secondary endpoints that broaden the research interest in retatrutide:
Knee Osteoarthritis
Participants reported significant improvements in knee pain scores, consistent with the hypothesis that weight reduction reduces mechanical joint load. Researchers have also noted interest in potential direct anti-inflammatory mechanisms as a separate area of investigation.
Obstructive Sleep Apnoea
Meaningful reductions in apnoea-hypopnoea index (AHI) were observed, adding to a growing body of evidence linking metabolic intervention to sleep-disordered breathing outcomes. This endpoint is of particular interest to researchers studying the systemic effects of metabolic receptor agonism beyond primary weight and glucose outcomes.
Comparative Context: Where Does Phase 3 Land?
| Compound | Receptor Targets | Peak Weight Reduction |
|---|---|---|
| Semaglutide 2.4mg | GLP-1 | ~15% (STEP 1, Phase 3) |
| Tirzepatide 15mg | GLP-1 / GIP | ~22.5% (SURMOUNT-1, Phase 3) |
| Retatrutide (TRIUMPH-1) | GLP-1 / GIP / Glucagon | ~28.3% (Phase 3, 80 weeks) |
The step-up from tirzepatide to retatrutide in Phase 3 data mirrors the directional signal from Phase 2, and the 80-week timeframe provides a more robust comparison point than earlier shorter-duration trials.
Research Considerations for RETAKLIK
Eurovits supplies RETAKLIK (Retatrutide) as a high-purity research material for qualified laboratories. For researchers working with this compound:
- Purity: All batches are independently lab-tested with COAs available on request
- Storage: Keep lyophilised material refrigerated and sealed; reconstitute with sterile bacteriostatic water
- Stability: Store reconstituted material at 2–8°C; avoid repeated freeze-thaw cycles
- Handling: Follow standard peptide research protocols