Key takeaways
- • Trial: SURMOUNT-5 (NCT05822830) — Phase 3b, 751 participants over 72 weeks.
- • Drug studied: Zepbound (Tirzepatide) — FDA-approved branded product.
- • Primary endpoint: Percent change in body weight at week 72 — tirzepatide vs semaglutide 2.4mg, head-to-head
- • Key result: Tirzepatide produced 20.2% mean weight loss vs 13.7% on semaglutide 2.4mg at 72 weeks (the first direct head-to-head RCT; tirzepatide superior). Gastrointestinal side-effect profiles were broadly similar and mostly mild-to-moderate.
- • Published: New England Journal of Medicine, 2025.
Study design
SURMOUNT-5 was a phase 3b randomized controlled trial enrolling 751 participants over 72 weeks. The trial studied Zepbound (Tirzepatide) for obesity / overweight and was published in New England Journal of Medicine in 2025.
Primary endpoint
Percent change in body weight at week 72 — tirzepatide vs semaglutide 2.4mg, head-to-head
Key results
| Measure | Value |
|---|---|
| Headline result | Tirzepatide produced 20.2% mean weight loss vs 13.7% on semaglutide 2.4mg at 72 weeks (the first direct head-to-head RCT; tirzepatide superior). Gastrointestinal side-effect profiles were broadly similar and mostly mild-to-moderate. |
| Mean weight loss (highest dose arm) | 20.2% |
| Participants | 751 |
| Duration | 72 weeks |
| Phase | Phase 3b |
Citation
SURMOUNT-5. Published in New England Journal of Medicine, 2025.
GLP1Zoom did not conduct this trial. We summarize published primary literature. For verbatim methods and full results, consult the primary publication and the ClinicalTrials.gov registry record.
Related
- Zepbound drug page — pricing, FDA status, side effects, alternatives
- All tirzepatide trials
- GLP-1 clinical trials database
Other Zepbound trials
- SURMOUNT-1 — Mean weight loss 15
- SURMOUNT-2 — Mean weight loss 12
- SURMOUNT-3 — Additional 18
- SURMOUNT-4 — Continued tirzepatide arm lost additional 5
Other Tirzepatide trials
- SURPASS-1 (Mounjaro) — HbA1c reduction 1
- SURPASS-2 (Mounjaro) — HbA1c reduction 2
- SURPASS-3 (Mounjaro) — HbA1c reduction 1
- SURPASS-4 (Mounjaro) — HbA1c reduction 2
Important: This trial was conducted on the FDA-approved branded product Zepbound. Compounded versions of Tirzepatide have NOT been studied in equivalent randomized controlled trials, and their efficacy and safety profile may differ.
GLP1Zoom is an affiliate-only comparator. We cite published trials; we do not conduct them. This page is informational and is not a substitute for personalized medical advice — always confirm any treatment decision with your prescribing clinician. Full disclaimer.