Retatrutide vs Tirzepatide vs Semaglutide: Full Comparison
Retatrutide, tirzepatide and semaglutide differ in receptor activity and regulatory status. Their headline trial results come from separate studies and are not interchangeable.
Comparison at a glance
| Characteristic | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Receptor targets | GLP-1 | GIP + GLP-1 | GIP + GLP-1 + glucagon |
| Selected obesity-trial mean | ~14.9% at 68 weeks | ~20.9% at 72 weeks | 24.2% at 48 weeks (Phase 2); 28.3% at 80 weeks in 2026 Phase 3 topline report |
| US regulatory status | Approved for specified indications | Approved for specified indications | Investigational; not FDA approved |
| Studied frequency | Once weekly | Once weekly | Once weekly |
| Highest dose in cited obesity trial | 2.4 mg | 15 mg | 12 mg |
What the glucagon receptor adds
Retatrutide’s glucagon receptor activity is intended to add energy-expenditure and hepatic-metabolism signaling to the appetite and glucose effects associated with GIP and GLP-1 activity. This creates a distinctive mechanism, but mechanism alone cannot establish superior clinical benefit or safety.
Retatrutide vs tirzepatide
Tirzepatide is a dual GIP/GLP-1 receptor agonist with FDA-approved indications and established prescribing information. Retatrutide adds glucagon receptor activity but remains investigational. Comparing the 24.2% Phase 2 retatrutide result with tirzepatide’s 20.9% selected obesity-trial result is descriptive only.
TRIUMPH-5 directly compares retatrutide with tirzepatide in adults with obesity. Its planned completion is later in 2026, making it the more appropriate source for comparative conclusions when results become available.
Retatrutide vs semaglutide
Semaglutide activates GLP-1 receptors and is supported by completed regulatory programs for specific uses. Retatrutide’s triple activity is biologically different, but the additional targets may add both effects and risks. No inference about an individual’s best treatment follows from receptor count.
The cross-trial comparison caveat
Study populations, treatment duration, background care, discontinuation rules and statistical estimands differ. Some figures are peer-reviewed; the 2026 Phase 3 figure is currently a sponsor-reported topline result. A responsible comparison keeps those distinctions visible.
Common questions
Is retatrutide better than tirzepatide?
That is not established. Headline results from separate trials are not a direct comparison, and retatrutide is not approved.
What is the difference from Ozempic?
Ozempic contains semaglutide, a GLP-1 receptor agonist. Retatrutide activates GIP, GLP-1 and glucagon receptors and remains investigational.
Is retatrutide stronger than Mounjaro?
Receptor count and separate-trial percentages do not prove clinical superiority. TRIUMPH-5 is designed to compare retatrutide and tirzepatide directly.
References
- Jastreboff AM, Kaplan LM, Frías JP, et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine. 2023;389:514–526.
- Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. New England Journal of Medicine. 2021;384:989–1002.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine. 2022;387:205–216.
- ClinicalTrials.gov. TRIUMPH-5: Retatrutide Compared With Tirzepatide in Adults With Obesity. NCT06662383.
- Eli Lilly and Company. TRIUMPH-1 Phase 3 topline results and American Diabetes Association 86th Scientific Sessions program update. May 2026.
References were checked against the journal, PubMed or ClinicalTrials.gov record. Company-reported topline results are labeled as such.