Bottom line
In the 72-week SURMOUNT-5 trial, tirzepatide produced greater average weight loss than semaglutide in adults with obesity or overweight without diabetes. That establishes greater average efficacy under the trial conditions. It does not make tirzepatide the best choice for every patient because treatment selection also depends on indication, contraindications, tolerability, coverage, cardiovascular history, and the ability to continue therapy. |
Why SURMOUNT-5 matters
Before SURMOUNT-5, comparisons often relied on separate trials conducted in different populations. SURMOUNT-5 directly randomized adults with obesity or overweight and weight-related complications, without diabetes, to tirzepatide or semaglutide. Both medications were escalated toward the maximum tolerated dose.
What the study found
At 72 weeks, tirzepatide produced significantly greater mean percentage weight reduction than semaglutide. More participants assigned to tirzepatide reached higher categorical weight-loss thresholds, and waist circumference declined more. Gastrointestinal adverse effects were common with both medications and were generally concentrated during dose escalation.
The correct interpretation is that tirzepatide was superior for average weight reduction in this specific trial population. The study was not designed to declare one product universally superior across every outcome, comorbidity, insurance plan, or patient preference.
Reasons Wegovy may still be the better individual choice
- A patient is doing well, tolerating treatment, and achieving clinically meaningful results on semaglutide.
- Coverage, availability, or out-of-pocket cost is better for Wegovy.
- The clinician is prioritizing an indication or evidence base particularly relevant to semaglutide for that patient.
- Tirzepatide previously caused unacceptable adverse effects.
- The patient prefers not to switch from an effective stable regimen merely to pursue a larger average trial result.
Reasons Zepbound may deserve consideration
- The patient needs greater weight reduction to address a serious obesity-related complication.
- Semaglutide produced inadequate benefit despite appropriate use and follow-up.
- Tirzepatide is accessible and clinically appropriate.
- The patient understands that greater average efficacy does not guarantee greater personal efficacy or tolerability.
- Patient may have cooccuring sleep apnea.
What about side effects?
Both medications commonly cause nausea, diarrhea, vomiting, constipation, abdominal discomfort, and other gastrointestinal effects. Individual tolerability can differ substantially. The best medication on paper is not the best medication if a patient cannot remain hydrated, eat adequately, function normally, or continue treatment.
Should a patient switch solely because tirzepatide won the trial?
Usually not. Switching an effective, tolerated treatment has costs and risks, including new prior authorization, interrupted supply, renewed dose escalation, and different adverse effects. A switch is more compelling when current results are inadequate, health goals require greater efficacy, or access materially favors the alternative.
Belite Clinical Perspective
SURMOUNT-5 gives clinicians a better efficacy comparison, but medication selection remains a clinical matching problem. The best treatment is the one that is effective enough, safe enough, tolerable enough, and affordable enough to continue. |
Frequently asked questions
Which caused more weight loss in the head-to-head study?
Tirzepatide produced greater average weight reduction than semaglutide at 72 weeks.
Does that mean Wegovy no longer works well?
No. Semaglutide remains a highly effective obesity medication with substantial clinical-outcomes evidence.
Can I switch directly from one medication to the other?
Switching should be planned with a clinician. Timing and starting dose depend on the prior dose, adverse effects, interruption length, and medical history.
Which one has fewer side effects?
Both commonly cause gastrointestinal side effects. Individual tolerability is more informative than a simple class-wide ranking.
How BeLite Can Help
Belite can compare efficacy, tolerability, medical history, access, and maintenance considerations before a patient starts or switches therapy.
BeLite can help patients translate emerging obesity-medicine evidence into an individualized plan that considers efficacy, tolerability, nutrition, muscle preservation, long-term maintenance, and access.
BeLite Medical Center has provided physician-supervised medical weight management in Fairfax, Virginia since 1995. Our clinic offers in-person medical supervision — with the ability to adjust medications and monitor your progress in real time — that fully virtual services cannot match.
Booking appointments is simple with our online scheduling portal, available 24/7 at the BeLite Medical Center scheduling website. You can also call or text us at (703) 359-9200, or email belitemed@gmail.com. We offer free consultations for new patients — if you choose not to enroll, there is no charge. We serve patients across Virginia, Maryland, Washington D.C., the DMV area, Pennsylvania, and West Virginia. Patients do not sign treatment contracts and can stop coming at any time.
Medical Disclaimer
This blog post is provided for informational purposes only and does not constitute medical advice, diagnosis, or treatment. It is not intended to substitute for consultation with a licensed healthcare provider. Readers should not use this information to diagnose or treat a medical or health condition without consulting an appropriately qualified healthcare professional. Any reliance on the information in this blog is at the reader’s own risk. Individual weight loss results vary based on personal health status and adherence to medical advice. No doctor-patient relationship is created by accessing or reading this content.
Primary references
- Aronne LJ, et al. Tirzepatide as compared with semaglutide for the treatment of obesity. N Engl J Med. 2025. doi:10.1056/NEJMoa2416394. Source
- gov. SURMOUNT-5: NCT05822830. Source
- Rodriguez PJ, et al. Semaglutide vs tirzepatide for weight loss in adults with overweight or obesity. JAMA Intern Med. 2024. Source
About BeLite Medical Center
BeLite Medical Center in Northern, VA helps you reach your weight loss goals.
