Retatrutide vs Tirzepatide
Comparison of approved tirzepatide and investigational retatrutide - dual vs triple incretin agonists.
Last updated: January 19, 2026
Retatrutide
Tirzepatide
Overview
Tirzepatide is FDA-approved while retatrutide is investigational. Retatrutide adds glucagon receptor agonism to the GIP/GLP-1 combination.
Mechanism Comparison
| Aspect | Tirzepatide | Retatrutide |
|---|---|---|
| Receptors | GIP + GLP-1 | GIP + GLP-1 + Glucagon |
| Class | Dual agonist | Triple agonist |
| Novel Element | First dual agonist | Adds glucagon |
Regulatory Status
| Aspect | Tirzepatide | Retatrutide |
|---|---|---|
| FDA Status | Approved | Phase 3 |
| Indications | T2D, Weight | None yet |
| Availability | Prescription | Investigational |
Weight Loss (Cross-Trial Comparison)
| Metric | Tirzepatide | Retatrutide |
|---|---|---|
| Max in trials | 22.5% | 24.2% |
| Trial | SURMOUNT-1 | Phase 2 |
| Duration | 72 weeks | 48 weeks |
Note: Not head-to-head; cross-trial comparison has limitations.
Glucagon Component Theory
Retatrutide’s glucagon receptor agonism may:
- Increase energy expenditure
- Enhance fat oxidation
- Provide thermogenic effects
- Accelerate weight loss beyond satiety
Summary
- Tirzepatide: Approved, proven, available now
- Retatrutide: Investigational, potentially greater efficacy, pending Phase 3
This comparison is for educational purposes only. Retatrutide is investigational.
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Disclaimer: This comparison is for educational purposes only and does not constitute medical advice. Individual responses to medications vary. Always consult a qualified healthcare provider before making treatment decisions.