Retatrutide vs Orforglipron
Side-by-Side Comparison
| Attribute | Retatrutide | Orforglipron |
|---|---|---|
| Category | Metabolic / Triple Agonist | Metabolic / Oral GLP-1 Agonist (Small Molecule) |
| Mechanism | Retatrutide simultaneously activates three receptors: GLP-1 (reduces appetite, slows gastric emptying, improves insulin secretion), GIP (enhances insulin sensitivity, glucose control), and glucagon... | Orforglipron is a non-peptide small molecule that acts as a full agonist at the GLP-1 receptor. Originally discovered by Chugai Pharmaceutical (as OWL833) and licensed to Eli Lilly, it binds to the... |
| Evidence Rating | B — Phase III / NDA Filed | B — Phase III / NDA Filed |
| Clinical Status | Phase 3 clinical trials (Eli Lilly TRIUMPH program) | Phase III (ATTAIN trial program for T2D and obesity). Eli Lilly expects regulatory submission based on ATTAIN results. |
| Safety Profile | GI side effects (dose-related, 13-63% across dose groups): nausea, vomiting, diarrhea, constipation; mostly mild to moderate; GI events partially mitigated with lower starting dose (2 mg vs 4 mg initial dose) | Common: nausea (30-40%), vomiting (14-22%), diarrhea (16-22%), constipation — consistent with GLP-1 class but lower than danuglipron BID; GI adverse events are dose-dependent and generally transient, most common during dose titration |
| Route | Subcutaneous (clinical trial formulation only) | Oral |
| Dose Range | Phase 2 tested 1, 4, 8, 12 mg weekly SC; optimal dose being determined in Phase 3 | 12–45 mg oral once daily (Phase 2 tested 12, 24, 36, 45 mg) |
| Frequency | Once weekly | Once daily |
| Molecular Weight | N/A | N/A |
| Half-Life | ~6 days (allows once-weekly dosing) | ~25-36 hours |
Overview
Retatrutide and Orforglipron are both research peptides studied across multiple applications. This comparison examines their mechanisms, evidence base, dosing protocols, and safety profiles to help researchers understand the key differences and overlaps.
Retatrutide — Mechanism & Evidence
Retatrutide is a first-in-class investigational triple hormone receptor agonist (GIP, GLP-1, and glucagon) developed by Eli Lilly. In the Phase 2 trial (Jastreboff et al., NEJM 2023, n=338), the 12 mg dose achieved 24.2% mean body weight reduction at 48 weeks, with 100% of participants achieving at least 5% weight loss. Multiple Phase 3 TRIUMPH trials are ongoing, with TRIUMPH-4 (Dec 2025) reporting average loss up to 71.2 lbs with osteoarthritis pain relief. Expected FDA approval is 2027-2028.
Key claims: Unprecedented weight loss in Phase 2; Phase 3 confirms efficacy with osteoarthritis benefit; Improves glycemic control in type 2 diabetes.
Orforglipron — Mechanism & Evidence
Orforglipron (LY3502970) is a small-molecule, non-peptide oral GLP-1 receptor agonist being developed by Eli Lilly. NOTE: Orforglipron is NOT a peptide — it is a synthetic small molecule included here for comparison with peptide-based GLP-1 agonists. It is in Phase III development (ATTAIN trial program) for type 2 diabetes and obesity. Orforglipron has shown promising Phase II results with weight loss approaching injectable GLP-1 agonists, and if approved, would be the first oral non-peptide GLP-1 agonist on the market. Once-daily dosing without food restrictions makes it potentially more convenient than oral semaglutide.
Key claims: Significant weight loss approaching injectable GLP-1 agonists; Effective glycemic control in T2D; Convenient once-daily oral dosing without food restrictions.
Shared Research Applications
Both peptides are studied for: Weight Management, Metabolic Health.
Retatrutide is also researched for: no additional unique applications.
Orforglipron is also researched for: no additional unique applications.
Safety Considerations
Retatrutide: GI side effects (dose-related, 13-63% across dose groups): nausea, vomiting, diarrhea, constipation; mostly mild to moderate GI events partially mitigated with lower starting dose (2 mg vs 4 mg initial dose) Dose-dependent heart rate increases peaking at 24 weeks, declining thereafter
Orforglipron: Common: nausea (30-40%), vomiting (14-22%), diarrhea (16-22%), constipation — consistent with GLP-1 class but lower than danuglipron BID GI adverse events are dose-dependent and generally transient, most common during dose titration Discontinuation due to GI adverse events: approximately 10-17% across dose groups, lower than danuglipron BID
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Related Research News
Retatrutide Clinical Trial Results: Phase III TRIUMPH Data Shows Significant Weight Loss
Early reports from the Phase III TRIUMPH-1 trial suggest retatrutide, a novel triple agonist, has delivered substantial weight loss outcomes. These retatrutide clinical trial results indicate a potential shift in obesity treatment research, though full data analysis is pending.
Retatrutide Phase III TRIUMPH-1 Results: Unprecedented Weight Loss Reported at ADA26
Early reports from the American Diabetes Association 2026 meeting suggest retatrutide delivered unprecedented weight loss in the Phase III TRIUMPH-1 trial. Researchers and industry professionals are closely watching these retatrutide clinical trial results for implications in obesity and metabolic disease treatment.
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