⚖️Tirzepatide
FDA-approved dual GIP/GLP-1 receptor agonist (Mounjaro/Zepbound). Up to 22.5% weight loss in SURMOUNT-1 trial. Currently the most effective approved anti-obesity medication.
GIP/GLP-1 dual agonistWhat Is Tirzepatide?
Tirzepatide (LY3298176) is a dual GIP/GLP-1 receptor agonist developed by Eli Lilly. FDA-approved as Mounjaro (T2D, 2022) and Zepbound (obesity, 2023). The SURMOUNT-1 trial demonstrated 22.5% body weight reduction at 72 weeks at 15mg — the highest for any approved pharmacological agent at the time.
Key Mechanisms
- GLP-1R agonism — appetite suppression and gastric emptying delay
- GIPR agonism — synergistically amplifies GLP-1R-mediated weight loss; adipose tissue effects
- Metabolic parameter improvement — HbA1c, triglycerides, blood pressure, HDL
Key References
- Jastreboff AM et al. "Tirzepatide once weekly for the treatment of obesity." N Engl J Med, 2022;387:205–216.
- Rosenstock J et al. "Efficacy and Safety of a Novel Dual GIP and GLP-1 Receptor Agonist Tirzepatide in T2DM." Lancet, 2021;398:143–155.
Frequently Asked Questions
No — semaglutide is a single (GLP-1-only) receptor agonist, while tirzepatide is a dual agonist activating both GIP and GLP-1 receptors. The added GIP mechanism underlies tirzepatide's larger weight-loss effect sizes in head-to-head trial data.
Both are tirzepatide — the same molecule under different brand names for different approved indications (Mounjaro for type 2 diabetes, Zepbound for chronic weight management), similar to the Ozempic/Wegovy relationship for semaglutide.
Tirzepatide combines GIP + GLP-1 agonism; retatrutide adds a third receptor (glucagon, GCGR) on top of that same dual mechanism, which is the basis for retatrutide's investigational higher weight-loss ceiling in Phase 2 data.