Obesity evidence dossier
Retatrutide
Best-in-class weight-loss potential if approved. The 104-week extension (30.3%) signals continued loss with longer exposure, but reflects a selected BMI>=35 completer subgroup in the 12-mg-to-MTD arm, so it is not directly comparable to the full 80-week estimand.
Total weight loss
25.0%
TRIUMPH-1 · 12 mg · week 80 · Includes treatment stops
Placebo-adjusted
21.1%
Difference from placebo in the same study when reported.
Study context
GIP/GLP-1/glucagon triple agonist/Adults with obesity or overweight, without diabetes/2339 participants across the study/80-week endpoint
Baseline: See the source for enrollment criteria
Ranked result & calculation
TRIUMPH-1 · 12 mg · 80 weeks
Adults with obesity or overweight, without diabetes. 2,339 participants across the study (not this dose arm alone).
Includes treatment stops. Treatment-policy results estimate outcomes regardless of stopping treatment.
- Average weight loss
- 25%
- Placebo group
- 3.9% loss
- Beyond placebo
- 21.1 percentage points (arm subtraction)
- Stopped due to adverse events
- Not verified for this result
Score: 70% × 95.0 total-loss points + 30% × 91.8 beyond-placebo points = 94/100, rounded. Conversion scales
Alternative analysis assuming continued treatment: 28.3% total loss. This is not the result used for the headline score. Alternative analysis source ↗
Lilly, TRIUMPH-1 ↗Phase 3 · Sponsor disclosure · Reviewed 2026-09-21
Evidence
Benchmark read
TRIUMPH-1: Includes treatment stops.
Diabetes data
Retatrutide is also being studied in people with type 2 diabetes; those weight-loss estimates should be interpreted separately from non-diabetic obesity trials.
Safety
Side effects and cautions
Discontinuation read
Adverse-event discontinuation has not been verified for this result.
Common side effects
Gastrointestinal events were the main tolerability issue; adverse-event discontinuation was 11.3% at 12 mg versus 4.9% with placebo.
Main cautions
Not approved. A US BLA submission is planned for Q1 2027. The 104-week extension result is a selected subgroup and should not be read as the overall effect.
Latest catalyst
Retatrutide Phase 3 TRIUMPH-1 shows 28.3% weight loss at 80 weeks; 30.3% in a 104-week extension
May 21, 2026
Lilly's retatrutide met the Phase 3 TRIUMPH-1 primary endpoint with 28.3% mean weight loss at 80 weeks on 12 mg (vs. 2.2% placebo), 25.9% on 9 mg, and 19.0% on 4 mg by the efficacy estimand. A prespecified extension in completers with baseline BMI ≥35 who tolerated assigned medication showed 30.3% mean weight loss at 104 weeks for the 12 mg-to-maximum-tolerated-dose group. Regulatory pathway, tolerability profile, and upcoming TRIUMPH trial readouts remain key factors for commercial positioning.
Linked clinical trials
Trials in the saddl3 obesity snapshot
Non-diabetic obesity studies are prioritized; diabetes and healthy-volunteer studies remain visible and labeled.
NCT06383390
Phase 3
The Effect of Retatrutide Once Weekly on Cardiovascular Outcomes and Kidney Outcomes in Adults Living With Obesity (TRIUMPH-Outcomes)
Eli Lilly and Company
Non-diabetic obesity
Mar 24, 2026
NCT06859268
Phase 3
A Study of Retatrutide (LY3437943) in the Maintenance of Weight Reduction in Individuals With Obesity
Eli Lilly and Company
Non-diabetic obesity
Mar 3, 2026
NCT05882045
Phase 3
A Study of Retatrutide (LY3437943) in Participants With Obesity and Cardiovascular Disease
Eli Lilly and Company
Non-diabetic obesity
Jul 23, 2025
NCT06662383
Phase 3
A Study of Retatrutide (LY3437943) Compared to Tirzepatide (LY3298176) in Adults Who Have Obesity
Eli Lilly and Company
Non-diabetic obesity
Apr 27, 2025
NCT05929066
Phase 3
A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight
Eli Lilly and Company
Non-diabetic obesity
Apr 18, 2025
NCT07035093
Phase 3
A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight and Chronic Low Back Pain
Eli Lilly and Company
Non-diabetic obesity
Mar 24, 2026
NCT07232719
Phase 3
A Study of Retatrutide (LY3437943) in Participants With Obesity or Overweight
Eli Lilly and Company
Non-diabetic obesity
Mar 20, 2026
NCT05931367
Phase 3
A Study of Retatrutide (LY3437943) Once Weekly in Participants Who Have Obesity or Overweight and Osteoarthritis of the Knee
Eli Lilly and Company
Non-diabetic obesity
Jan 21, 2026
NCT04881760
Phase 2
A Study of LY3437943 in Participants Who Have Obesity or Are Overweight
Eli Lilly and Company
Non-diabetic obesity
Sep 13, 2023
NCT06313528
Phase 1
A Study to Measure Calorie Consumption and Usage in Participants With Obesity Using LY3437943
Eli Lilly and Company
Non-diabetic obesity
Sep 23, 2025
NCT06039826
Phase 1
A Study of LY3437943 in Postmenopausal Female Participants Who Are Overweight or Obese
Eli Lilly and Company
Non-diabetic obesity
Jul 26, 2024
NCT05548231
Phase 1
A Study of LY3437943 in Chinese Participants With Obesity Or Overweight
Eli Lilly and Company
Non-diabetic obesity
Aug 14, 2023