Trial review
SURMOUNT-5: Tirzepatide vs Semaglutide Head to Head
Tirzepatide versus semaglutide, head to head
SURMOUNT-5 was a phase 3b, randomised, open-label, active-controlled head-to-head funded by Eli Lilly and Company. Least-squares mean weight change of −20.2% with tirzepatide versus −13.7% with semaglutide (P<0.001); −22.8 kg versus −15.0 kg; waist circumference −18.4 cm versus −13.0 cm. That figure belongs to the population, dose, comparator and 72 weeks shown below, and describes a group average under trial conditions rather than a prediction for any individual.
| Design | Phase 3b, randomised, open-label, active-controlled head-to-head |
|---|---|
| Population | Adults with obesity but without type 2 diabetes; BMI 30 or above, or 27 or above with at least one obesity-related complication. 32 sites in the United States and Puerto Rico, April 2023 to November 2024 |
| Sample size | 751 randomised 1:1 |
| Intervention | Tirzepatide once weekly at maximum tolerated dose |
| Comparator | Semaglutide once weekly at maximum tolerated dose, 1.7 mg or 2.4 mg |
| Duration | 72 weeks |
| Primary endpoint | Percentage change in body weight from baseline at week 72 |
| Main result | Least-squares mean weight change of −20.2% with tirzepatide versus −13.7% with semaglutide (P<0.001); −22.8 kg versus −15.0 kg; waist circumference −18.4 cm versus −13.0 cm |
Show this figure as a table
| Step | Stage | What happens |
|---|---|---|
| 1 | Who was eligible | Adults with obesity but without type 2 diabetes; BMI 30 or above, or 27 or above with at least one obesity-related complication. 32 sites in the United States and Puerto Rico, April 2023 to November 2024 |
| 2 | What they received | Tirzepatide once weekly at maximum tolerated dose |
| 3 | What it was compared against | Semaglutide once weekly at maximum tolerated dose, 1.7 mg or 2.4 mg |
| 4 | For how long | 72 weeks |
| 5 | What was measured first | Percentage change in body weight from baseline at week 72 |
| 6 | What the group average was | Least-squares mean weight change of −20.2% with tirzepatide versus −13.7% with semaglutide (P<0.001); −22.8 kg versus −15.0 kg; waist circumference −18.4 cm versus −13.0 cm |
| 7 | What it does not tell you | A group average is not a prediction for any individual reader. |
Show this figure as a table
| Item | Weight change | Evidence |
|---|---|---|
| Tirzepatide, % weight change | 20% | Verified |
| Semaglutide, % weight change | 14% | Verified |
| Question | Position |
|---|---|
| Average effect in the studied population | Reported once captured |
| Your individual outcome | Not predicted by any trial |
| Effect of a compounded preparation | Not studied here |
| Effect at doses outside the protocol | Not studied here |
| Effect after stopping | Only if the trial included a withdrawal phase |
| Long-term safety beyond the trial | Outside the observation window |
Who was studied
- Inclusion and exclusion criteria in plain language. Say who was not studied — that is usually the more useful half.
What was given, and what it was compared against
- Dose, titration schedule, comparator, and whether the comparator was placebo or an active drug.
Results
- Primary endpoint first, with absolute numbers alongside percentages. Secondary endpoints labelled as secondary.
Adverse events and discontinuations
- Never omitted for length. Report discontinuation rates alongside efficacy.
Limitations
- Funding, blinding, dropout handling, generalisability, duration.
How this should and should not be read
- Explicitly address the misreadings this trial commonly attracts.
How it compares with other trials
- Only where designs are comparable. Say so when they are not.
- Retrieve the registry record and the peer-reviewed publication. Record NCT, DOI and PMID.
- Do not summarise from a manufacturer press release, a conference abstract described as a result, or a news article.
- Where only topline or preprint data exists, label it as such everywhere it appears, including the direct answer.
- Medical review is mandatory on this page before publication.
Questions readers actually ask
Does this mean I would lose that much weight?
No. Trials report group averages under controlled conditions with specific eligibility criteria. Individual results vary widely, and the trial population may not resemble you.
Do these results apply to compounded tirzepatide?
Not automatically. Trials studied the approved product at studied doses. A compounded preparation at a different concentration, formulation or route has not been through those trials.
Related on this site
- Research hubResearch
- SURMOUNT-1 Tirzepatide Trial ExplainedResearch
- SURMOUNT-3 Tirzepatide Trial ExplainedResearch
- SURMOUNT-4: Weight Maintenance and Tirzepatide WithdrawalResearch
- How rankings are computedCore & Trust
- All-in cost toolTools
- Price records, machine-readableData
- Tirzepatide and Heart Failure With Preserved Ejection FractionJournal
- Tirzepatide and Fatty Liver / MASHResearch
- Tirzepatide and Diabetes Prevention Over 176 WeeksJournal
GLP-1 Tirzepatide Review. “SURMOUNT-5: Tirzepatide vs Semaglutide Head to Head.” S.J Partners LLC, 2026-07-24. https://glp1tirzepatidereview.com/research/surmount-5/
When quoting a figure, include the capture date shown beside it rather than the date you read this page. A price without its capture date is not a usable citation.