Tirzepatide vs. Semaglutide at 72 Weeks: A Head-to-Head Analysis of the Data
Medically Reviewed by
Board Certified Endocrinologist
Published
Dec 5, 2025
Last Reviewed
Mar 17, 2026
Sources
5 peer-reviewed
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YMYL / E-E-A-T
Tirzepatide vs. Semaglutide: Which Produces More Weight Loss?
At 72 weeks, tirzepatide (Zepbound/Mounjaro 15mg) produces 20.9% average body weight loss vs. 14.9% for semaglutide (Wegovy 2.4mg) — a clinically significant 6-percentage-point difference. For a 250-lb person, that translates to roughly 52 lbs vs. 37 lbs. Tirzepatide's advantage comes from its dual GLP-1/GIP receptor mechanism. However, semaglutide has established cardiovascular outcomes data that tirzepatide's CVOT has not yet reported.
The Trials Behind the Comparison
Comparing tirzepatide and semaglutide requires understanding the trials that produced the data. SURMOUNT-1 (tirzepatide/Zepbound) enrolled 2,539 adults without diabetes and ran for 72 weeks. STEP 1 (semaglutide/Wegovy) enrolled 1,961 adults without diabetes and ran for 68 weeks. While not a direct head-to-head trial (different patient populations, slightly different durations), they provide the best available comparison of these two leading medications.
Weight Loss: The Numbers
At maximum doses over approximately 72 weeks: Tirzepatide 15 mg produced 20.9% average body weight loss (SURMOUNT-1). Semaglutide 2.4 mg produced 14.9% average body weight loss (STEP 1). The difference of approximately 6 percentage points is clinically significant. For a 250-lb patient, that translates to roughly 52 lbs lost on tirzepatide vs. 37 lbs on semaglutide — a 15-lb difference that is meaningful for most patients.
Why the Difference? The Dual Agonist Advantage
Tirzepatide activates both GLP-1 and GIP receptors, while semaglutide activates only GLP-1. GIP (glucose-dependent insulinotropic polypeptide) adds additional mechanisms for appetite suppression and metabolic improvement beyond what GLP-1 alone provides. This dual-agonist approach appears to produce greater appetite reduction and more favorable metabolic effects, resulting in the higher average weight loss.
Side Effect Comparison
Both medications share a similar GI side effect profile, but with nuanced differences. Nausea rates are comparable (approximately 20–30% for both). Tirzepatide causes more sulfur burps and bloating. Semaglutide may cause slightly more constipation. Both improve substantially after the first 8–12 weeks. Discontinuation rates due to side effects were low in both trials (4–7%).
How to Choose Between Them
The choice between tirzepatide and semaglutide often comes down to insurance coverage, availability, and individual response. Tirzepatide offers greater average weight loss but may not be covered by your insurance. Semaglutide has the proven cardiovascular benefit (SELECT trial) that tirzepatide hasn't yet established. Some patients respond better to one than the other, and switching is reasonable if initial results are disappointing.
Frequently Asked Questions
These answers are for informational purposes only. Always consult your physician for personalized medical advice.
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Scientific References & Further Reading
- Wilding JPH et al. — Once-Weekly Semaglutide in Adults with Overweight or Obesity. NEJM 2021.
- Jastreboff AM et al. — Tirzepatide Once Weekly for the Treatment of Obesity. NEJM 2022.
- FDA Drug Approvals Database — GLP-1 Receptor Agonists. U.S. Food & Drug Administration.
- PubMed — GLP-1 Receptor Agonist Research Index. National Library of Medicine.
- Mayo Clinic — Semaglutide (GLP-1 Agonist): Uses, Side Effects, and Dosing. Mayo Clinic Drug Reference.
This content is produced in accordance with GLP-1 Health's editorial standards and is based on peer-reviewed clinical evidence from the sources cited above. It does not constitute medical advice. Always consult a licensed healthcare provider before starting any medication.
