Retatrutide (LY3437943) \u2014 Eli Lilly's triple agonist \u2014 showed ~24.2% weight loss in Phase 2, the highest ever recorded in the GLP-1 class. Here is the complete TRIUMPH Phase 3 program tracker, timeline, and estimated FDA approval outlook.
TRIUMPH-1 and TRIUMPH-2 are actively enrolling and in follow-up. Primary endpoint data (72-week weight loss) is expected in late 2026 to Q1 2027. TRIUMPH-3 (cardiovascular outcomes) and TRIUMPH-4 (NASH/MASH) are in design phase. Analyst consensus estimates an NDA submission in late 2027 and FDA approval in 2027\u20132028, assuming Phase 3 data confirms Phase 2 efficacy (~24.2% weight loss at 12 mg).
LY3437943 identified as triple agonist candidate; IND filed
First-in-human single/multiple ascending dose study; safety and PK established
48-week obesity trial; 12 mg dose shows ~24.2% weight loss — highest in class
Retatrutide 12 mg: HbA1c −2.0%, weight −16.9% at 36 weeks in T2D population
TRIUMPH-1 and TRIUMPH-2 begin enrollment; TRIUMPH-3 and -4 in design
Full enrollment achieved; primary endpoint follow-up period underway
72-week primary endpoint data expected; NDA preparation begins
Eli Lilly submits NDA for obesity indication; Priority Review possible
Standard review: ~12 months from NDA; Priority Review: ~6 months
The Phase 2 obesity trial (NCT05394519, published in NEJM 2023) is the benchmark against which TRIUMPH-1 will be judged. The 12 mg dose showed ~24.2% mean body weight reduction at 48 weeks. Phase 3 trials typically enroll broader populations and may show modest regression from Phase 2 results.
| Dose | Weight Loss at 24 wks | Weight Loss at 48 wks | GI Discontinuation | Nausea Rate |
|---|---|---|---|---|
| 1 mg | ~5.2% | ~8.7% | ~2% | ~25% |
| 4 mg | ~10.4% | ~17.3% | ~5% | ~38% |
| 8 mg | ~14.1% | ~22.8% | ~8% | ~47% |
| 12 mg ★ | ~17.5% | ~24.2% | ~12% | ~58% |
| Placebo | ~1.6% | ~2.1% | ~1% | ~14% |
\u2605 = expected Phase 3 maintenance dose. Data from NCT05394519 (NEJM 2023). Phase 3 results may differ.
| Parameter | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Mechanism | GLP-1 (single) | GLP-1 + GIP (dual) | GLP-1 + GIP + Glucagon (triple) |
| Phase 2 weight loss | ~15% (STEP 1) | ~22.5% (SURMOUNT-1) | ~24.2% (Phase 2, 48 wks) |
| Phase 3 program | STEP (complete) | SURMOUNT (complete) | TRIUMPH (ongoing) |
| FDA approval status | Approved (Ozempic/Wegovy) | Approved (Mounjaro/Zepbound) | Phase 3 — est. 2027–2028 |
| Nausea rate | ~30–44% | ~33–45% | ~47–58% |
| GI discontinuation | ~5–8% | ~6–9% | ~8–12% (Phase 2) |
| CV outcomes trial | SELECT (complete) | SURPASS-CVOT (complete) | TRIUMPH-3 (design phase) |
| NASH indication | ESSENCE trial (ongoing) | SURPASS-NASH (ongoing) | TRIUMPH-4 (design phase) |
| Manufacturer | Novo Nordisk | Eli Lilly | Eli Lilly |
Phase 3 weight loss data may be lower than Phase 2 (~24.2%) due to broader population selection. A result below ~20% would narrow differentiation from tirzepatide.
Glucagon receptor agonism increases heart rate (~3–5 bpm in Phase 2). TRIUMPH-3 will be critical; any MACE signal could require label restrictions.
Phase 2 showed ~12% GI discontinuation at 12 mg — higher than tirzepatide (~6–9%). Phase 3 real-world adherence may be lower than trial conditions.
Glucagon receptor agonism is a novel mechanism in approved obesity drugs. FDA may request additional data on hepatic effects, bone density, or long-term safety.
As of April 2026, retatrutide (LY3437943) is in Phase 3 clinical development. The TRIUMPH program includes TRIUMPH-1 (obesity without T2D), TRIUMPH-2 (obesity with T2D), TRIUMPH-3 (cardiovascular outcomes), and TRIUMPH-4 (NASH/MASH). TRIUMPH-1 and TRIUMPH-2 are the most advanced, with primary completion expected in late 2026 to early 2027. Eli Lilly has not yet announced a formal NDA submission date, but analysts estimate a submission in late 2027 with potential approval in 2027–2028.
In the Phase 2 trial (NCT05394519), retatrutide 12 mg demonstrated approximately 24.2% mean body weight reduction at 48 weeks — the highest weight loss ever recorded for a GLP-1 class agent in a Phase 2 trial. The Phase 3 program is designed to confirm these findings across a larger, more diverse population with longer follow-up.
TRIUMPH is Eli Lilly's Phase 3 program for retatrutide. TRIUMPH-1 targets obesity without T2D; TRIUMPH-2 targets obesity with T2D; TRIUMPH-3 is a cardiovascular outcomes trial (MACE endpoint); and TRIUMPH-4 targets NASH/MASH. Additional sub-studies evaluate sleep apnea, kidney disease, and HFpEF.
Based on current Phase 3 timelines, analyst consensus estimates an NDA submission in late 2027, with potential approval in 2027–2028. This assumes TRIUMPH-1 and TRIUMPH-2 complete primary endpoints on schedule (late 2026–early 2027), followed by a 6–12 month NDA preparation and a standard 10–12 month FDA review. A Priority Review designation is possible given the obesity indication.
Retatrutide is a triple agonist (GLP-1 + GIP + glucagon) while tirzepatide is a dual agonist (GLP-1 + GIP). The glucagon component increases energy expenditure and hepatic fat mobilization. In Phase 2, retatrutide 12 mg showed ~24.2% weight loss vs tirzepatide's ~22.5% in SURMOUNT-1. Phase 3 will determine whether this advantage holds and whether the higher nausea burden (~47–58% vs ~33–45%) affects adherence.
Yes — retatrutide is available as a research compound from licensed peptide suppliers such as Purgo Labs. Research-grade retatrutide is manufactured to pharmaceutical specifications with third-party COA verification. It is sold strictly for in vitro and preclinical research and is not approved for human use.
Key risks: (1) Phase 3 weight loss below Phase 2 (~24.2%), narrowing differentiation from tirzepatide; (2) cardiovascular safety signals in TRIUMPH-3 — glucagon agonism raises heart rate ~3–5 bpm; (3) higher GI discontinuation at the 12 mg dose; (4) FDA requesting additional glucagon agonism data; and (5) manufacturing scale-up challenges.
Purgo Labs provides pharmaceutical-grade retatrutide (LY3437943) with third-party COAs from accredited US labs confirming \u226599% purity. Available while Phase 3 trials continue. Use code HEALTH for 15% off.
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