Tirzepatide (Zepbound)
GLP-1 + GIP agonist · Eli Lilly
Top dose
15 mg
Weight loss
-22.5%
at week 72 · treatment regimen
AE discontinuation
6.2%
Status
approved
Weight loss trajectory #
Pivotal trial #
- Trial
- SURMOUNT-1
- Indication
- obesity (no T2D)
- Duration
- 72 weeks
- ClinicalTrials.gov
- NCT04184622
- Sponsor
- Eli Lilly
Dose-response: weight loss vs AE-led discontinuation #
Per-arm efficacy (bars, left axis) and AE-led discontinuation (dots, right axis) from SURMOUNT-1 (Jastreboff NEJM 2022). Higher doses generally trade extra weight loss for worse tolerability.
Notes #
SURMOUNT-1 (Jastreboff NEJM 2022) is the registrational obesity paper. SURMOUNT-5 head-to-head vs semaglutide (Aronne NEJM 2025, NEJMoa2416394, n=751, 72-wk): tirzepatide -20.2% vs semaglutide -13.7%, P<0.001 - cleanest direct evidence of tirz's 6.5pp efficacy advantage.