Comparison Report: Semaglutide vs Tirzepatide vs Retatrutide
8/9/2026
| Feature | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Brand Names | Ozempic®, Wegovy® | Mounjaro® | N/A (Investigational) |
| Manufacturer | Novo Nordisk | Eli Lilly | Eli Lilly |
| Drug Class | GLP-1 receptor agonist | Dual GIP/GLP-1 receptor agonist | Triple GIP/GLP-1/Glucagon receptor agonist |
| Mechanism of Action | Mimics GLP-1 to stimulate insulin, reduce glucagon, slow gastric emptying, and suppress appetite | Mimics both GIP and GLP-1 for enhanced insulin release, satiety, and glucose control | Activates GIP, GLP-1, and glucagon receptors to improve metabolism, suppress appetite, and boost energy expenditure |
| Dosing | Weekly injection (0.25–2.4 mg) | Weekly injection (2.5–15 mg) | Weekly injection (in trials: 1–12 mg) |
| FDA Approval | Approved: • Ozempic for Type 2 diabetes • Wegovy for obesity | Approved: • Mounjaro for Type 2 diabetes • FDA Fast Track for obesity | Not yet approved (Phase 2 trials ongoing) |
| Clinical Use | • Type 2 diabetes • Obesity/Weight management | • Type 2 diabetes • Obesity (pending full approval) | • Obesity (in trials) |
| Weight Loss (avg) | ~15% body weight (Wegovy) | ~22.5% body weight (SURMOUNT-1) | ~24.2% body weight (Phase 2 trial, 48 weeks) |
| Glucose Control (HbA1c) | ↓ ~1.5–2.0% | ↓ ~2.0–2.4% | Not primary focus, but also lowers glucose |
| Common Side Effects | • Nausea • Vomiting • Constipation • Fatigue | • Nausea • Diarrhea • Reduced appetite • Mild hypoglycemia | • GI effects (nausea, vomiting) • Potential lean mass loss • Still under study |
| Advantages | • Well-studied • Effective • Cardiovascular benefit | • Greater weight loss than semaglutide • Dual action may offer synergistic effect | • Most potent weight loss to date • May boost metabolism via glucagon receptor |
| Limitations | • GI side effects • Plateau in weight loss | • GI side effects • Expensive | • Early-stage • Long-term safety unknown |
🔍 Summary:
- Semaglutide: The most widely prescribed and studied. Great for patients starting on GLP-1 therapy. Proven cardiovascular and metabolic benefits.
- Tirzepatide: Outperforms semaglutide in both blood sugar control and weight loss. Considered next-gen GLP-1 therapy.
- Retatrutide: Most promising for obesity treatment, with early data showing >24% weight loss. However, still in clinical trials and not yet available to the public.