Semaglutide vs. Tirzepatide
A head-to-head comparison of the two most effective GLP-1 weight loss medications. Semaglutide targets one incretin pathway; tirzepatide targets two. Here is how they compare on efficacy, side effects, dosing, and clinical evidence.
| Feature | Semaglutide | Tirzepatide |
|---|---|---|
| Drug Class | GLP-1 receptor agonist | Dual GLP-1/GIP receptor agonist |
| Brand Names | Wegovy (weight), Ozempic (diabetes) | Zepbound (weight), Mounjaro (diabetes) |
| Mechanism | Single incretin pathway (GLP-1) | Dual incretin pathways (GLP-1 + GIP) |
| Administration | Weekly subcutaneous injection | Weekly subcutaneous injection |
| Target Dose | 2.4 mg/week | 5 mg, 10 mg, or 15 mg/week |
| Titration Period | 16-20 weeks to maintenance | 20-24 weeks to maximum dose |
| Avg. Weight Loss | ~15-17% of body weight | ~20-26% of body weight |
| Onset of Effect | Noticeable within 4-8 weeks | Noticeable within 4-8 weeks |
| Nausea Rate | Up to 44% | Up to 33% |
| Duration of Effect | 7-day half-life | 5-day half-life |
| CV Outcomes Data | Yes (SELECT trial — 20% MACE reduction) | Not yet (SURPASS-CVOT ongoing) |
| FDA Weight Approval | June 2021 | November 2023 |
| Boxed Warning | Thyroid C-cell tumors (rodent) | Thyroid C-cell tumors (rodent) |
Key Differences
Mechanism
Semaglutide targets only GLP-1 receptors. Tirzepatide is a dual agonist, activating both GLP-1 and GIP receptors. This dual action appears to produce greater appetite suppression and enhanced fat metabolism.
Weight Loss Efficacy
Head-to-head data (SURMOUNT vs. STEP) suggests tirzepatide produces approximately 5-8 percentage points more weight loss. SURMOUNT-1 showed 20.9% at highest dose vs. STEP 1 at 14.9%.
GI Tolerability
Tirzepatide appears to have lower rates of nausea (33% vs. 44%) despite greater weight loss. Both medications are best tolerated with gradual dose titration.
Cardiovascular Data
Semaglutide has proven CV benefit from the SELECT trial (20% MACE reduction). Tirzepatide's dedicated CV outcomes trial is still in progress.
Dosing Flexibility
Tirzepatide offers three maintenance dose options (5, 10, 15 mg) vs. one target dose for semaglutide (2.4 mg), providing more flexibility for individualized therapy.
Track Record
Semaglutide has a longer clinical history with more extensive post-marketing safety data. Tirzepatide is newer but represents the next generation of incretin therapy.
The Bottom Line
Both semaglutide and tirzepatide are highly effective, FDA-approved medications for chronic weight management. Tirzepatide appears to produce greater average weight loss with comparable or better GI tolerability, while semaglutide has stronger cardiovascular outcomes data and a longer clinical track record. The choice between them should be made with a healthcare provider based on your individual health profile, treatment goals, insurance coverage, and medication availability.
Neither medication is a standalone solution — both work best as part of a comprehensive approach that includes dietary modifications, physical activity, and ongoing medical supervision.
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Get startedThis comparison is for educational purposes only and is not medical advice. Drug efficacy data is derived from separate clinical trials with different study populations and cannot be directly compared. Always consult your healthcare provider. Last reviewed: March 2026.