Semaglutide vs Tirzepatide
Semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) are the two most prescribed GLP-1 medications for weight loss and type 2 diabetes. The head-to-head SURMOUNT-5 trial settled the efficacy question — tirzepatide produces greater weight loss — but the choice between them involves cost, availability, tolerability, and individual response.
Semaglutide
A GLP-1 receptor agonist FDA-approved for type 2 diabetes and chronic weight management, one of the most widely prescribed peptide drugs.
Tirzepatide
A dual GIP/GLP-1 receptor agonist FDA-approved for diabetes and weight management, producing the largest weight loss seen in clinical trials.
| Category | Semaglutide | Tirzepatide |
|---|---|---|
| Mechanism | GLP-1 receptor agonist (single) | GIP + GLP-1 dual receptor agonist |
| FDA-Approved For | Type 2 diabetes (Ozempic), weight management (Wegovy) | Type 2 diabetes (Mounjaro), weight management (Zepbound) |
| Weight Loss (Head-to-Head) | 13.7% at 72 weeks (SURMOUNT-5) | 20.2% at 72 weeks (SURMOUNT-5) |
| Cardiovascular Data | SELECT trial: 20% MACE reduction (proven) | SURPASS-CVOT ongoing; no hard outcomes data yet |
| GI Tolerability | Nausea common (~40%), especially during dose escalation | Generally better tolerated; GIP component may buffer nausea |
| Oral Option | Yes — oral semaglutide (Rybelsus 14mg, Wegovy 25mg pill) | Not yet; oral tirzepatide in development |
| Dosing | Once weekly injection (0.25–2.4mg) | Once weekly injection (2.5–15mg) |
| Cost (US Brand) | ~$1,000–$1,350/month | ~$1,000–$1,200/month |
| Compounded Availability | Widely available as compounded semaglutide | Emerging compounded options |
| Long-Term Safety Data | Extensive (5+ years of post-marketing data) | Growing but less than semaglutide |
Summary
The SURMOUNT-5 head-to-head trial definitively showed tirzepatide produces greater weight loss than semaglutide (20.2% vs 13.7% at 72 weeks). However, semaglutide has two advantages tirzepatide currently lacks: proven cardiovascular benefit from the SELECT trial (20% reduction in major cardiac events) and an oral formulation. For patients where cardiovascular risk reduction is the primary goal, semaglutide has stronger evidence. For maximum weight loss, tirzepatide is superior. GI tolerability tends to be better with tirzepatide — the GIP receptor component appears to counterbalance some GLP-1 nausea. Cost is similar for brand versions; compounded semaglutide is more widely available and often less expensive. The practical choice often comes down to insurance coverage, availability, whether an oral option matters, and how much weight loss is needed. Both are excellent medications — this is a choice between good and better, not good and bad.
These peptides are often used together. See our stack profiles for combination details.