Trial programme
The SURMOUNT Tirzepatide Trial Programme
SURMOUNT is the obesity trial programme for tirzepatide. Six trials define it: SURMOUNT-1 in obesity without diabetes, SURMOUNT-2 with diabetes, SURMOUNT-3 after lifestyle intervention, SURMOUNT-4 for withdrawal, SURMOUNT-5 head-to-head against semaglutide, and SURMOUNT-OSA in sleep apnoea. Together they cover efficacy, population differences, maintenance, and comparison.
Key takeaways
- Six SURMOUNT trials cover distinct questions rather than repeating the same design.
- Effect size varies by population: about 20.9% without diabetes versus 12.8-14.7% with diabetes.
- SURMOUNT-4 is the maintenance evidence; SURMOUNT-5 is the comparison evidence.
- All six studied the FDA-approved product at labelled doses.
- No SURMOUNT trial studied a compounded product or a dose below 5 mg.
| Trials in programme | 6 catalogued here |
|---|---|
| Largest | SURMOUNT-1, N=2,539 |
| Longest randomised phase | 72 weeks (SURMOUNT-1, -2, -3, -5) |
| Dose range studied | 5, 10, and 15 mg weekly |
| Sponsor | Eli Lilly and Company (all) |
What does the programme cover?
| Trial | Population | N | Result | Identifiers |
|---|---|---|---|---|
| SURMOUNT-1 | Adults with obesity or overweight, without type 2 diabetes | 2,539 | Mean weight reduction up to about 20.9% at 15 mg vs 3.1% placebo | NCT04184622 · PMID 35658024 · DOI |
| SURMOUNT-2 | Adults with obesity or overweight AND type 2 diabetes | 938 | Mean weight reduction about 12.8% to 14.7% vs 3.2% placebo | NCT04657003 · PMID 37385274 · DOI |
| SURMOUNT-3 | Adults with obesity/overweight without diabetes who first lost at least 5% with lifestyle intervention | 579 | Substantial additional reduction after lifestyle lead-in; 87.5% achieved a further 5% or more vs 16.5% placebo | NCT04657016 · DOI |
| SURMOUNT-4 | Adults with obesity or overweight, without type 2 diabetes | 670 | Continued treatment maintained and modestly extended weight loss; withdrawal to placebo produced substantial regain | NCT04660643 · PMID 38078870 · DOI |
| SURMOUNT-5 | Adults with obesity or overweight with a weight-related comorbidity, without diabetes | 751 | Tirzepatide superior to semaglutide for weight and waist circumference at week 72 (waist -18.4 cm vs -13.0 cm) | NCT05822830 · PMID 40353578 · DOI |
| SURMOUNT-OSA | Adults with obesity and moderate-to-severe obstructive sleep apnoea (AHI 15 or higher) | 469 | Significant reduction in apnoea-hypopnoea index vs placebo, with weight, hypoxic burden, hsCRP and systolic blood-pressure improvements | NCT05412004 · PMID 38912654 · DOI |
Why did the programme need six trials?
Because each answers a question the others cannot. Efficacy in a general obesity population (SURMOUNT-1) says nothing about diabetes (SURMOUNT-2), about what happens after lifestyle change (SURMOUNT-3), about stopping (SURMOUNT-4), about how it compares with the main alternative (SURMOUNT-5), or about a specific comorbidity (SURMOUNT-OSA). Reading any one trial as the whole picture is the most common error in consumer coverage.
What the evidence shows
- Tirzepatide produces large mean weight reduction at labelled doses across populations.
- Effect is dose-related within the studied 5-15 mg range.
- Continued treatment is required to maintain the result (SURMOUNT-4).
What the evidence does not show
- That results transfer to compounded tirzepatide or to doses below 5 mg.
- That every individual achieves the mean — variation around it is wide.
- That weight outcomes by themselves establish cardiovascular benefit.
How large is the effect across the verified trials?
| Trial arm | Point estimate | Range | N |
|---|---|---|---|
| SURMOUNT-1 · 15 mg | 20.9% | 19.5% to 22.3% | 2,539 |
| SURMOUNT-1 · 10 mg | 19.5% | 18.2% to 20.8% | 2,539 |
| SURMOUNT-1 · 5 mg | 15.0% | 13.8% to 16.2% | 2,539 |
| SURMOUNT-2 · 15 mg | 14.7% | 13.4% to 16.0% | 938 |
| SURMOUNT-2 · 10 mg | 12.8% | 11.5% to 14.1% | 938 |
| SURMOUNT-1 · placebo | 3.1% | 2.3% to 3.9% | 2,539 |
| Series | Wk 0 | Wk 12 | Wk 24 | Wk 40 | Wk 56 | Wk 72 |
|---|---|---|---|---|---|---|
| Tirzepatide 15 mg | 0% | -6.5% | -12.4% | -16.8% | -19.3% | -20.9% |
| Tirzepatide 5 mg | 0% | -5.1% | -9.3% | -12.4% | -14.2% | -15.0% |
| Placebo | 0% | -1.4% | -2.3% | -2.8% | -3.0% | -3.1% |
When was each piece of this evidence established?
| Date | Event |
|---|---|
| May 2022 | Tirzepatide approved as Mounjaro for type 2 diabetes |
| Jun 2022 | SURMOUNT-1 published in the New England Journal of Medicine |
| Jul 2023 | SURMOUNT-2 published in the Lancet |
| Nov 2023 | Tirzepatide approved as Zepbound for chronic weight management |
| Dec 2023 | SURMOUNT-4 withdrawal results published in JAMA |
| Jun 2024 | SURMOUNT-OSA published; obstructive sleep apnoea evidence established |
| May 2025 | SURMOUNT-5 head-to-head against semaglutide published in NEJM |
What does this page cover, and what does it deliberately leave out?
This page addresses Obesity trial map, populations, doses and outcomes and limitations, organised around the primary question of SURMOUNT trials. Each of those elements is treated separately below rather than blended, because they carry different evidence weights and a reader is entitled to know which parts rest on randomised data and which rest on a captured commercial claim or a regulatory document.
| Element | Treatment here | Evidence basis |
|---|---|---|
| Obesity trial map | Covered on this page | Primary evidence |
| Populations | Covered on this page | Primary evidence |
| Doses | Covered on this page | Primary evidence |
| Outcomes and limitations | Covered on this page | Primary evidence |
| Individualized clinical instruction | Deliberately not covered | Belongs with the registered protocol and the peer-reviewed publication |
What are the limits of what this page can tell you?
Every page on this site rests on a specific primary trial record, and that record has boundaries worth stating plainly rather than leaving a reader to discover them. The limitations below are specific to the material presented above.
- The evidence here describes groups, populations, or captured records — it does not describe you, and no page can substitute for the registered protocol and the peer-reviewed publication.
- Figures carry the date on which they were verified. In a market where terms change frequently, an undated figure functions as a claim about the present that nobody has checked.
- Elements marked Verification Pending are genuinely unknown to this publication rather than merely omitted for brevity, and should not be inferred from surrounding content.
- Where a source conflicts with another, this site shows the conflict rather than resolving it, which means some questions are left open on purpose.
What would change the conclusion on this page?
This page would be revised, with the change recorded in its history, if any of the following occurred:
- New primary evidence bearing directly on SURMOUNT trials.
- A change to FDA labelling affecting any statement made above.
- A verified correction submitted through the corrections process and accepted on the evidence.
- A material change to a captured record, including a price, term, or regulatory status.
- Completion of a verification currently marked pending, which would replace a gap with a stated fact.
What do the technical terms on this page mean?
Definitions for the 5 technical terms this page uses, including DOI, PMID, apnoea-hypopnoea index, compounded — in the specific sense used above.
| DOI | Digital Object Identifier. A persistent link to a specific published article that continues to resolve even if the journal reorganises its website. |
|---|---|
| PMID | PubMed Identifier. A number that locates the peer-reviewed publication of a study in the PubMed database. |
| apnoea-hypopnoea index | The number of breathing interruptions per hour of sleep, measured by polysomnography. It was the primary endpoint in SURMOUNT-OSA. |
| compounded | Prepared by a pharmacy rather than manufactured under an approved application. Compounded tirzepatide is not FDA approved and has not been evaluated in any randomised trial. |
| placebo | An inactive comparator given so that the effect of the drug can be separated from the effect of being in a trial. Placebo groups in the SURMOUNT trials still lost some weight, which is why the placebo-subtracted difference matters more than the raw figure. |
Frequently asked questions
What is the SURMOUNT programme?
The set of phase 3 trials testing tirzepatide for obesity and related conditions, numbered SURMOUNT-1 through -5 plus condition-specific trials such as SURMOUNT-OSA.
Which SURMOUNT trial is most relevant to me?
SURMOUNT-1 if you have obesity without diabetes; SURMOUNT-2 if you have type 2 diabetes; SURMOUNT-4 if you are asking what happens after stopping.
Were all SURMOUNT trials funded by the manufacturer?
Yes — Eli Lilly and Company sponsored the programme. That is disclosed on every trial page and does not by itself invalidate results.
Did any SURMOUNT trial study compounded tirzepatide?
No. Compounded tirzepatide is not FDA approved and is not reviewed by the FDA for safety, effectiveness, or quality before sale.
Change history
| Date | Change |
|---|---|
| 2026-07-22 | Page published with current dataset snapshot. |
Dates change only for substantive edits, never for cosmetic changes. Corrections: corrections policy.