Brenipatide vs Retatrutide
Brenipatide (LY3537031) and Retatrutide (LY3437943) are two of the newest long-acting incretin peptides. Retatrutide activates three receptors, GIP, GLP-1 and glucagon, and has published phase 3 obesity results. Brenipatide activates two, GIP and GLP-1, lasts longer in the body, and is being tested mainly in addiction, mood disorders, schizophrenia and asthma. This page compares them as research compounds.
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| Brenipatide | Retatrutide | |
|---|---|---|
| Development code | LY3537031 | LY3437943 |
| Receptor targets | GIP and GLP-1 (dual) | GIP, GLP-1 and glucagon (triple) |
| Reported half-life | 9 to 12 days (phase 1) | About 6 days (phase 1b) |
| Main trial focus | Alcohol, opioid and smoking studies, mood disorders, schizophrenia, asthma | Obesity, type 2 diabetes and related conditions |
| Published efficacy data | None yet | TRIUMPH-1: 17.6% to 25.0% at 80 weeks (placebo 3.9%) |
| Status | Phase 3 (alcohol use disorder, major depressive disorder) | Phase 3; a US filing is planned for early 2027 |
| Peptx availability | Not stocked, waitlist on this page | UK single vials and Factory Direct kits |
- Development code
- LY3537031LY3437943
- Receptor targets
- GIP and GLP-1 (dual)GIP, GLP-1 and glucagon (triple)
- Reported half-life
- 9 to 12 days (phase 1)About 6 days (phase 1b)
- Main trial focus
- Alcohol, opioid and smoking studies, mood disorders, schizophrenia, asthmaObesity, type 2 diabetes and related conditions
- Published efficacy data
- None yetTRIUMPH-1: 17.6% to 25.0% at 80 weeks (placebo 3.9%)
- Status
- Phase 3 (alcohol use disorder, major depressive disorder)Phase 3; a US filing is planned for early 2027
- Peptx availability
- Not stocked, waitlist on this pageUK single vials and Factory Direct kits
Two receptors or three
Both compounds activate the GIP and GLP-1 receptors. Retatrutide adds the glucagon receptor, which in animal studies raises energy expenditure and fat breakdown in the liver. That third target is a large part of why retatrutide's weight results are the highest reported for any incretin compound so far.
Brenipatide stays with the two incretin receptors and is built for a long half-life instead: 9 to 12 days in phase 1 data presented at Psych Congress 2026, against about 6 days reported for retatrutide in its phase 1b study.
Different questions, different trials
Retatrutide's TRIUMPH programme is about obesity and its complications. TRIUMPH-1, published in the New England Journal of Medicine in September 2026, enrolled 2,339 adults and reported weight reductions of 17.6%, 23.7% and 25.0% at 80 weeks, against 3.9% on placebo.
Brenipatide's RENEW programme asks whether incretin signalling changes behaviour and inflammation: alcohol use disorder and major depressive disorder in phase 3, and smoking relapse, opioid use disorder, bipolar disorder, schizophrenia and asthma in phase 2. None of these trials has reported, and none compares brenipatide with retatrutide.
Why the two get compared
Both are next-generation, long-acting incretin peptides, so they are often grouped together in discussion of what comes after tirzepatide. On current evidence they are not alternatives: retatrutide is the obesity compound with phase 3 data, and brenipatide is a dual agonist whose efficacy in any condition is still unknown.
Bottom line for research labs
Retatrutide and Brenipatide answer different questions. Retatrutide is the triple agonist with the largest published weight effect of any incretin compound. Brenipatide is a longer-lasting dual agonist being tested in addiction, mood and asthma, with no efficacy data yet. For metabolic research today, retatrutide is the documented choice; brenipatide is the one to watch as the RENEW trials report.