Short answer: In the 72-week SURMOUNT-5 head-to-head trial in adults with obesity without diabetes, tirzepatide produced greater average weight loss than semaglutide: 20.2% versus 13.7%. That result supports greater average efficacy under the trial conditions; it does not mean tirzepatide is safer, affordable, or best for every patient.
Commercial terms and coverage information were checked August 12, 2026 and can change. This article is educational and is not medical advice.
What the direct trial found
| SURMOUNT-5 result | Tirzepatide | Semaglutide |
|---|---|---|
| Participants | 751 adults with obesity, without type 2 diabetes | |
| Treatment | Maximum tolerated 10 or 15 mg weekly | Maximum tolerated 1.7 or 2.4 mg weekly |
| Average weight change at 72 weeks | -20.2% | -13.7% |
| Most common adverse events | Gastrointestinal; mostly mild to moderate and concentrated during dose escalation | |
The trial was open-label and funded by Eli Lilly. It tested specific maximum-tolerated dose strategies in a defined population, not every dose or patient group.
What “better” can mean
For average weight reduction in that trial, tirzepatide was better. A personal choice also depends on FDA-approved indication, cardiovascular or sleep-apnea considerations, contraindications, side effects, pregnancy plans, other medication, insurance coverage, supply, and ability to continue treatment. These factors can outweigh the difference in trial averages.
Brand and indication matter
For chronic weight management, the relevant U.S. brands are Wegovy for semaglutide and Zepbound for tirzepatide. Ozempic and Mounjaro use the same respective active ingredients but have different approved indications. Do not compare or substitute them only by ingredient name.
Check your GLP-1 eligibility
Use our free BMI Calculator to see if you may qualify for provider-reviewed GLP-1 therapy.
Try the BMI Calculator →Questions for the prescriber
- Which product is approved for my diagnosis?
- Which contraindications or interactions apply?
- What side effects should trigger a call or urgent care?
- What will my plan cover after prior authorization?
- What is the plan if I cannot tolerate dose escalation?
Frequently asked questions
Which caused more weight loss in the direct trial?
Tirzepatide: 20.2% average weight loss versus 13.7% with semaglutide at 72 weeks in SURMOUNT-5.
Does that mean tirzepatide is best for everyone?
No. Trial averages do not determine individual safety, tolerability, coverage, or medical suitability.
Were the drugs compared at every dose?
No. SURMOUNT-5 used maximum tolerated tirzepatide 10 or 15 mg and semaglutide 1.7 or 2.4 mg.
Were people with diabetes included?
No. The SURMOUNT-5 population in this comparison had obesity without type 2 diabetes.
Are compounded versions equivalent to Wegovy or Zepbound?
No. Compounded products are not FDA approved and should not be described as equivalent FDA-approved products.
Sources
- SURMOUNT-5, New England Journal of Medicine — direct 72-week efficacy and adverse-event results.
- Wegovy Prescribing Information — indications, contraindications, warnings, and dosing.
- Zepbound Prescribing Information — indications, contraindications, warnings, and dosing.
- FDA — differences and concerns for unapproved GLP-1 products.
Editorial method: FormBlends Editorial Standards Team reviewed official program pages, regulatory material, prescribing information, and primary research where applicable. No clinician or patient review is claimed.
See your options in about 2 minutes
Take the free quiz and see what fits you. Quick, private, and no commitment to continue.
See my options →