--- title: "TRIUMPH-1: Retatrutide Phase 3 Results | Primara Labs" url: https://www.primaralabs.com/research/trials/triumph-1 source: Primara Labs, markdown mirror of the HTML page --- # TRIUMPH-1 In TRIUMPH-1, a phase 3 trial of retatrutide in adults with obesity, or overweight with at least one weight-related condition, without diabetes (n=2,339), mean body weight fell 19.0% on 4 mg, 25.9% on 9 mg and 28.3% on 12 mg over 80 weeks, against 2.2% on placebo (efficacy estimand; Eli Lilly topline release, 21 May 2026). Primara Labs sells some of the compounds covered here. Every figure on this page links to its source and the date it was checked. Updated 24 September 2026 Retatrutide Explained: Triple Agonist Research (Philippines Guide)1:50·[Transcript and chapters](https://www.primaralabs.com/videos/retatrutide) ## Results Mean percent change in body weight by arm, as each source reports it. Navy bars are the trial arms, grey bars the comparator. Bars from different trials are not a head-to-head comparison: populations, durations and estimands differ. ## Side effects reported In TRIUMPH-1, discontinuation because of adverse events was 4.1% on 4 mg, 6.9% on 9 mg and 11.3% on 12 mg, against 4.9% on placebo. The most frequently reported adverse events were nausea in 28.6% on 4 mg, 38.4% on 9 mg and 42.4% on 12 mg against 14.8% on placebo, diarrhoea in 25.2% on 4 mg, 34.1% on 9 mg and 32.0% on 12 mg against 13.5% on placebo, constipation in 23.8% on 4 mg, 25.9% on 9 mg and 26.1% on 12 mg against 10.9% on placebo and vomiting in 10.6% on 4 mg, 22.8% on 9 mg and 25.3% on 12 mg against 4.8% on placebo. | Event | 4 mg | 9 mg | 12 mg | Placebo | | --- | --- | --- | --- | --- | | Discontinuation for adverse events | 4.1% | 6.9% | 11.3% | 4.9% | | Nausea | 28.6% | 38.4% | 42.4% | 14.8% | | Diarrhoea | 25.2% | 34.1% | 32.0% | 13.5% | | Constipation | 23.8% | 25.9% | 26.1% | 10.9% | | Vomiting | 10.6% | 22.8% | 25.3% | 4.8% | | Dysesthesia | 5.1% | 12.3% | 12.5% | 0.9% | | Urinary tract infection | 7.5% | 8.8% | 8.4% | 5.3% | Design ## Trial design and sources Compound Retatrutide Phase 3 Population Adults with obesity, or overweight with at least one weight-related condition, without diabetes Participants randomised 2,339 Duration 80 weeks Primary endpoint Percent change in body weight from baseline at 80 weeks Estimand efficacy Read out 21 May 2026 A pre-specified extension of 532 participants with a baseline BMI of 35 or more reached -30.3% on 12 mg at 104 weeks (efficacy estimand). The treatment-regimen estimand at 80 weeks was -17.6%, -23.7% and -25.0% against -3.9% on placebo. - Eli Lilly topline release, 21 May 2026 [open](https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-delivered-powerful-weight-loss) · checked 23 September 2026 - ClinicalTrials.gov NCT05929066 [open](https://clinicaltrials.gov/study/NCT05929066) · checked 23 September 2026 - Registry: NCT05929066 Questions ## TRIUMPH-1, answered ### What did TRIUMPH-1 find? In TRIUMPH-1, a phase 3 trial of retatrutide in adults with obesity, or overweight with at least one weight-related condition, without diabetes (n=2,339), mean body weight fell 19.0% on 4 mg, 25.9% on 9 mg and 28.3% on 12 mg over 80 weeks, against 2.2% on placebo (efficacy estimand; Eli Lilly topline release, 21 May 2026). ### What side effects were reported in TRIUMPH-1? In TRIUMPH-1, discontinuation because of adverse events was 4.1% on 4 mg, 6.9% on 9 mg and 11.3% on 12 mg, against 4.9% on placebo. The most frequently reported adverse events were nausea in 28.6% on 4 mg, 38.4% on 9 mg and 42.4% on 12 mg against 14.8% on placebo, diarrhoea in 25.2% on 4 mg, 34.1% on 9 mg and 32.0% on 12 mg against 13.5% on placebo, constipation in 23.8% on 4 mg, 25.9% on 9 mg and 26.1% on 12 mg against 10.9% on placebo and vomiting in 10.6% on 4 mg, 22.8% on 9 mg and 25.3% on 12 mg against 4.8% on placebo. Related ## More on retatrutide - [TRIUMPH-2](https://www.primaralabs.com/research/trials/triumph-2) - [TRIUMPH-3](https://www.primaralabs.com/research/trials/triumph-3) - [TRIUMPH-4](https://www.primaralabs.com/research/trials/triumph-4) - [Retatrutide phase 2 (Jastreboff)](https://www.primaralabs.com/research/trials/retatrutide-phase-2) - [TRIUMPH-5](https://www.primaralabs.com/research/trials/triumph-5) - [TRIUMPH-6](https://www.primaralabs.com/research/trials/triumph-6) - [TRIUMPH-7](https://www.primaralabs.com/research/trials/triumph-7) - [TRIUMPH-8](https://www.primaralabs.com/research/trials/triumph-8) - [TRIUMPH-9](https://www.primaralabs.com/research/trials/triumph-9) - [TRIUMPH-OUTCOMES](https://www.primaralabs.com/research/trials/triumph-outcomes) - [Evidence Map: Retatrutide](https://www.primaralabs.com/research/evidence#retatrutide) - [Retatrutide 20mg](https://www.primaralabs.com/marketplace/retatrutide) ## More videos Retatrutide vs Tirzepatide vs Semaglutide: Trials Compared (PH)1:55·[Transcript and chapters](https://www.primaralabs.com/videos/reta-vs-tirz-vs-sema)