Tirzepatide Before and After: Weight Loss Results by Week
Tirzepatide before and after results are recorded at trial milestones, with no full weekly percentage table found in the fetchable sources reviewed. Every outcome figure below is a trial-level mean or proportion, not a promise for any one person. In the SURMOUNT-1 obesity trial, 2,539 adults started at a mean body weight of 104.8 kg. After 72 weeks, at the 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) doses, the average weight reduction ranged from about 15.0% to 20.9% on the conservative treatment-regimen estimand (PMID 35658024), or from 16.0% to 22.5% on the on-treatment efficacy estimand (efficacy estimand, ClinicalTrials.gov NCT04184622), against placebo losses of 3.1% on the treatment-regimen estimand (PMID 35658024) and 2.4% on the efficacy estimand (ClinicalTrials.gov NCT04184622). This page walks that timeline through the recorded milestones. It also shows how widely people differed, separates fat from lean mass, and explains why an individual before-and-after can differ from the trial average.
This is general education, not medical advice, and not a forecast of your results. The outcome figures on this page are means and proportions from the SURMOUNT-1 and SURMOUNT-4 trials. Tirzepatide is a prescription medicine. Nothing here is a dose to copy, a protocol, or a claim about what you will lose. If you are weighing any of this, the decision belongs with a licensed clinician, not a webpage.
2,539
adults randomised in SURMOUNT-1 (PMID 35658024)
72 weeks
trial length, with a 20-week escalation (PMID 35658024)
Averages
trial means, not a personal result
One number, two ways to count it
Every SURMOUNT-1 and SURMOUNT-4 weight result exists in two forms, and they are not interchangeable. The treatment-regimen estimand counts everyone who was randomised, whether or not they kept taking the drug or started other therapy, so it is the smaller, more conservative figure and the one the journal abstracts headline. The efficacy estimand estimates the effect if the drug is taken as directed, so it is the larger figure, and it is what ClinicalTrials.gov posts as the primary result. Both are real. The tables below keep the treatment-regimen and efficacy results separate.
What Before and After Means
The before in a tirzepatide trial is a measured baseline, not a memory. SURMOUNT-1 was a 72-week phase 3 randomised, double-blind trial in 2,539 adults with obesity, or with overweight plus at least one weight-related complication, and it excluded people with diabetes. Participants were assigned in equal groups to once-weekly subcutaneous tirzepatide at 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), or 15 mg (trial dose, not a recommendation, PMID 35658024), or to placebo. The protocol included a 20-week dose-escalation period (PMID 35658024).1 At baseline the mean body weight was 104.8 kg, the mean body mass index was 38.0, and 94.5% of participants had a body mass index of 30 or higher.1
Tirzepatide is a once-weekly subcutaneous injectable, and the deeper drug profile lives on our tirzepatide overview. This page is not a head-to-head comparison. For how it measures up against other options, see tirzepatide versus semaglutide and retatrutide versus tirzepatide. Here the single question is what the trials recorded before and after, and how much that varies from one person to the next.
Weight Change by Week
No full week-by-week table of SURMOUNT-1 weight was found in the fetchable sources reviewed. The accessible records provide a baseline, one intermediate milestone at week 20, the week-72 result, and a description of the curve shape; the NEJM full text and appendix, where any weekly table would sit, were not reachable. The timeline below is built only from those published points, so the intermediate weeks carry a description rather than an invented percentage.
| Timepoint | What the SURMOUNT-1 sources show |
|---|---|
| Week 0 (baseline) | Mean body weight 104.8 kg, mean body mass index 38.0; 94.5% of participants had a body mass index of 30 or higher (PMID 35658024). |
| Weeks 1 to 4 | The ZEPBOUND FDA label lists a once-weekly starting dose of 2.5 mg (labelled dose, not a recommendation, ZEPBOUND FDA label). The FDA Medical Review, NDA 217806, Reference ID 5274339, reports that SURMOUNT-1 used the same starting dose. The FDA medical reviewer reports that separation from placebo is apparent as early as week 4. |
| Week 4 | Per the FDA Medical Review (NDA 217806), the SURMOUNT-1 arm assigned 5 mg (trial dose, not a recommendation, PMID 35658024) reached maintenance at week 4, when separation from placebo became apparent. |
| Week 12 | Per the FDA Medical Review (NDA 217806), the SURMOUNT-1 arm assigned 10 mg (trial dose, not a recommendation, PMID 35658024) reached maintenance at week 12. |
| Week 20 | Per the FDA Medical Review (NDA 217806), the SURMOUNT-1 arm assigned 15 mg (trial dose, not a recommendation, PMID 35658024) reached maintenance at week 20, ending the 20-week dose-escalation period described in the trial abstract (PMID 35658024). ClinicalTrials.gov NCT04184622 reports that the pooled SURMOUNT-1 arms assigned 10 mg (trial dose, not a recommendation, PMID 35658024) and 15 mg (trial dose, not a recommendation, PMID 35658024) were down about 13.2 kg (least-squares mean, efficacy estimand, ClinicalTrials.gov NCT04184622) versus 2.5 kg on placebo (efficacy estimand, ClinicalTrials.gov NCT04184622). |
| Around week 60 | The FDA medical reviewer describes a plateau in the tirzepatide weight curves around week 60 and in the placebo curve near week 20 (FDA Medical Review, NDA 217806). |
| Week 72 | Final average weight change by dose (see the by-dose table below). |
Baseline from PMID 35658024; week-20 kilogram change from ClinicalTrials.gov NCT04184622. The PubMed abstract (PMID 35658024) states a 20-week dose-escalation period. The ZEPBOUND FDA label lists a starting dose of 2.5 mg (labelled dose, not a recommendation, ZEPBOUND FDA label) and increments of 2.5 mg (labelled dose, not a recommendation, ZEPBOUND FDA label), with at least four weeks between increases. The FDA Medical Review, NDA 217806, Reference ID 5274339, reports that SURMOUNT-1 used the same starting dose and increment size, with increases every four weeks. The trial schedule, maintenance weeks, and curve shape come from that review.
That gap is deliberate on this page. The weeks between 20 and 72, such as 24, 36, 48, and 60, appear in the fetchable sources only as a line on a graph, with no extractable underlying numbers in the records reviewed, so no percentage is placed on them here.278
The FDA medical reviewer described the shape plainly: the weight curves separate from placebo as early as week 4. The ZEPBOUND FDA label lists increments of 2.5 mg (labelled dose, not a recommendation, ZEPBOUND FDA label) from a starting dose of 2.5 mg (labelled dose, not a recommendation, ZEPBOUND FDA label), with at least four weeks between increases. The FDA Medical Review, NDA 217806, Reference ID 5274339, reports the same starting dose and increment size in SURMOUNT-1, with increases every four weeks. Per that review, the SURMOUNT-1 arms assigned 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) reached maintenance at weeks 4, 12, and 20, respectively. The tirzepatide curves keep falling until they plateau around week 60, while placebo plateaus near week 20.8 On that FDA-reviewed SURMOUNT-1 schedule, a photo taken at week 12 captures someone assigned to 15 mg (trial dose, not a recommendation, PMID 35658024) still in dose escalation, before the reported plateau.
Results by Dose at 72 Weeks
This is the before-and-after most people picture. In SURMOUNT-1, adults were assigned to once-weekly tirzepatide at 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), or 15 mg (trial dose, not a recommendation, PMID 35658024), or to placebo, and the table below shows the average percent weight change from baseline to week 72 by arm. Both estimands are shown so the figure is never quoted without its meaning.
| Arm | Treatment-regimen (headline) | Efficacy (on-treatment) |
|---|---|---|
| Placebo | -3.1% (PMID 35658024) | -2.4% (ClinicalTrials.gov NCT04184622) |
| SURMOUNT-1 tirzepatide 5 mg (trial dose, not a recommendation, PMID 35658024) | -15.0% (PMID 35658024) | -16.0% (ClinicalTrials.gov NCT04184622) |
| SURMOUNT-1 tirzepatide 10 mg (trial dose, not a recommendation, PMID 35658024) | -19.5% (PMID 35658024) | -21.4% (ClinicalTrials.gov NCT04184622) |
| SURMOUNT-1 tirzepatide 15 mg (trial dose, not a recommendation, PMID 35658024) | -20.9% (PMID 35658024) | -22.5% (ClinicalTrials.gov NCT04184622) |
In SURMOUNT-1, the treatment-regimen values at week 72 with 95% confidence intervals were: at 5 mg (trial dose, not a recommendation, PMID 35658024), -15.0% (-15.9 to -14.2); at 10 mg (trial dose, not a recommendation, PMID 35658024), -19.5% (-20.4 to -18.5); at 15 mg (trial dose, not a recommendation, PMID 35658024), -20.9% (-21.8 to -19.9); and placebo -3.1% (-4.3 to -1.9) (PMID 35658024). The efficacy-estimand least-squares means are from ClinicalTrials.gov NCT04184622.
The gap between doses is real but modest: calculated from the SURMOUNT-1 abstract figures, 5.9 percentage points separate the 5 mg (trial dose, not a recommendation, PMID 35658024) and 15 mg (trial dose, not a recommendation, PMID 35658024) arms at week 72 on the treatment-regimen estimand (-15.0% versus -20.9%, PMID 35658024), and the ClinicalTrials.gov figures give a calculated gap of 6.5 points on the efficacy estimand (-16.0% versus -22.5%, ClinicalTrials.gov NCT04184622). The FDA statistical reviewer reproduced those treatment-regimen figures for the same trial arms (FDA Statistical Review, NDA 217806).71 SURMOUNT-1 assigned doses of 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024). ClinicalTrials.gov NCT04184622 reports that body mass index fell by least-squares means of 5.9, 8.1, and 8.6 kg/m² in those arms, respectively, versus 0.9 kg/m² on placebo (efficacy estimand).2
The Spread Between People
Averages hide the range, and the range is the whole story for a before-and-after. Under the efficacy estimand at week 72, the share of participants reaching each threshold of weight loss looked like this.
| Threshold | Placebo | SURMOUNT-1 5 mg (trial dose, not a recommendation, PMID 35658024) | SURMOUNT-1 10 mg (trial dose, not a recommendation, PMID 35658024) | SURMOUNT-1 15 mg (trial dose, not a recommendation, PMID 35658024) |
|---|---|---|---|---|
| At least 5% loss | 27.87% | 89.41% | 96.18% | 96.32% |
| At least 10% loss | 13.54% | 73.35% | 85.85% | 90.08% |
| At least 15% loss | 5.98% | 50.24% | 73.61% | 78.24% |
| At least 20% loss | 1.26% | 31.62% | 55.48% | 62.88% |
Assigned doses in SURMOUNT-1 (trial dose, not a recommendation, PMID 35658024). Efficacy estimand, percentage of participants, week 72 (ClinicalTrials.gov NCT04184622).
Read the bottom row carefully. In SURMOUNT-1, at the 15 mg (trial dose, not a recommendation, PMID 35658024) dose, about 63% of participants reached at least 20% weight loss on the efficacy estimand, which means more than a third did not, and roughly 10% did not reach even 10% (efficacy estimand, ClinicalTrials.gov NCT04184622).2 Placebo is not zero either: under the treatment-regimen estimand, 35% of placebo participants reached at least 5% loss, and 3% reached at least 20% (PMID 35658024). On that same conservative estimand, at least 5% loss was reached by 85% at 5 mg (trial dose, not a recommendation, PMID 35658024), 89% at 10 mg (trial dose, not a recommendation, PMID 35658024), and 91% at 15 mg (trial dose, not a recommendation, PMID 35658024).1 If your own result is lagging the averages, our note on not losing weight on a GLP-1 covers the common reasons.
Fat, Lean Mass, and Waist
A scale number is not what a photo shows. A DXA substudy of SURMOUNT-1 scanned 160 participants at baseline and week 72 to separate fat from lean mass. The values below are pooled tirzepatide versus placebo, as percent change at week 72.
| Measure | Tirzepatide (pooled) | Placebo | Difference vs placebo (percentage points) (full text, PMC11965027) |
|---|---|---|---|
| Fat mass (full text, PMC11965027) | -33.9% | -8.2% | -25.7 (95% CI -31.4 to -20.0) |
| Lean mass (full text, PMC11965027) | -10.9% | -2.6% | -8.3 (95% CI -10.6 to -6.1) |
| Visceral fat mass (full text, PMC11965027) | -40.1% | -7.3% | -32.8 (95% CI -42.8 to -22.8) |
Full text PMC11965027 (open-access DXA substudy, PMID 39996356). ETD is the estimated treatment difference relative to placebo, in percentage points of percent change; the visceral-fat and confidence-interval figures are drawn from the open-access full text. The figures above are as given in the PMC11965027 full text.
In absolute terms, the open-access full text reports the pooled tirzepatide group lost about 15.9 kg of fat and 5.6 kg of lean mass, versus 3.6 kg and 1.2 kg on placebo, from tirzepatide-group baselines of 46.6 kg fat and 50.8 kg lean mass; placebo baselines were 49.4 kg fat and 53.0 kg lean mass (PMC11965027).3 The composition of the loss was similar in both arms, roughly 74% fat and 26% lean with tirzepatide and 75% fat and 25% lean on placebo (full text, PMC11965027); tirzepatide simply drove far more total loss. Waist circumference, which is closer to what a photo captures, fell at the 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) doses by about 14.6 cm, 19.4 cm, and 19.9 cm at week 72, versus 3.4 cm on placebo (efficacy estimand, ClinicalTrials.gov NCT04184622),2 and the DXA substudy measured a pooled waist reduction of about 18.1 cm from a baseline of 111.5 cm, reported in the open-access full text (PMC11965027).3
After Stopping: SURMOUNT-4
SURMOUNT-4 measured how durable the weight reduction was when treatment continued versus stopped. It ran a 36-week open-label lead-in on tirzepatide at the maximum tolerated dose of 10 mg (trial dose, not a recommendation, PMID 38078870) or 15 mg (trial dose, not a recommendation, PMID 38078870), during which 670 completers reached a mean weight reduction of 20.9% from a starting weight of 107.3 kg. It then randomised them to continue tirzepatide or switch to placebo for another year.4
| Group after randomisation | Weight change, week 36 to 88 | Kept at least 80% of lead-in loss |
|---|---|---|
| Continued tirzepatide | -5.5% (treatment-regimen, PMID 38078870) | 89.5% (treatment-regimen, PMID 38078870) |
| Switched to placebo | +14.0% (treatment-regimen, PMID 38078870) | 16.6% (treatment-regimen, PMID 38078870) |
Treatment-regimen estimand, week 36 to week 88, PMID 38078870.
The difference between the groups was 19.4 percentage points on the treatment-regimen estimand.4 On the efficacy estimand the split was similar, a change of -6.7% for those who continued versus +14.8% for those switched to placebo, a difference of 21.4 points, and most of the regain in the placebo group had already happened by week 64.5 The authors put it plainly: withdrawing tirzepatide led to substantial regain of lost weight, whereas continued treatment maintained and augmented initial weight reduction.4
Why Your Results May Differ
Put the pieces together and it is clear why an individual before-and-after can differ from a trial chart.
- The published numbers are group averages (least-squares means with small standard errors), not what any single person will get.
- The spread is wide. In SURMOUNT-1, at the 15 mg (trial dose, not a recommendation, PMID 35658024) dose, about 63% reached at least 20% loss on the efficacy estimand, so more than a third did not, and roughly 10% did not reach even 10% (efficacy estimand, ClinicalTrials.gov NCT04184622).
- Dose changes the average: in SURMOUNT-1, the 5 mg (trial dose, not a recommendation, PMID 35658024) and 15 mg (trial dose, not a recommendation, PMID 35658024) arms differed by 5.9 percentage points of mean weight loss at week 72 on the treatment-regimen estimand (-15.0% versus -20.9%, PMID 35658024) and by 6.5 points on the efficacy estimand (-16.0% versus -22.5%, ClinicalTrials.gov NCT04184622).
- Timing changes the picture: per the FDA medical reviewer, separation from placebo is apparent as early as week 4, the top dose is not reached until week 20, and loss continues to about week 60 (FDA Medical Review, NDA 217806), so a photo at week 12 shows someone in the SURMOUNT-1 15 mg (trial dose, not a recommendation, PMID 35658024) arm still escalating.
- In the 160-person SURMOUNT-1 DXA substudy, what is lost is mostly fat: roughly three quarters of the weight lost was fat mass (PMID 39996356). In the full trial, waist fell by about 14.6 to 19.9 cm depending on dose, and shape is what a photo shows (efficacy estimand, ClinicalTrials.gov NCT04184622).
- Results in SURMOUNT-4 depended on staying on the drug: the group switched to placebo after the lead-in regained a mean of about 14% of body weight over the following year, while those who continued kept losing (PMID 38078870).
- Tolerability filters who continues: across the tirzepatide arms of SURMOUNT-1, 4.3% to 7.1% of participants discontinued for adverse events (PMID 35658024), so before-and-after sets are biased toward people who tolerated treatment.
One filter deserves its own line. In SURMOUNT-1 the most common adverse events were gastrointestinal, mostly mild to moderate and concentrated in the escalation weeks. In its 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) arms, adverse events led 4.3%, 7.1%, and 6.2% of participants, respectively, to stop treatment, versus 2.6% on placebo (PMID 35658024).1 The Zepbound prescribing information reports any gastrointestinal reaction in 56% of treated patients at each dose versus 30% on placebo, with most nausea, vomiting, and diarrhea occurring during dose escalation and easing over time (FDA prescribing information).6 For how those effects present and settle, see our GLP-1 side effects guide.
The Short Version
- Tirzepatide before and after numbers come from SURMOUNT-1 and SURMOUNT-4, and every outcome figure is a trial-level mean or proportion, not a personal forecast.
- In SURMOUNT-1 at week 72, mean weight reduction at the 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) doses was about 15.0%, 19.5%, and 20.9% on the conservative treatment-regimen estimand (PMID 35658024), or 16.0%, 21.4%, and 22.5% on the efficacy estimand (efficacy estimand, ClinicalTrials.gov NCT04184622), versus placebo losses of 3.1% on the treatment-regimen estimand (PMID 35658024) and 2.4% on the efficacy estimand (ClinicalTrials.gov NCT04184622).
- No full weekly table was found in the fetchable sources reviewed; the accessible records provide weight at baseline, week 20, and week 72, plus a plotted trajectory for the weeks in between. The NEJM full text and appendix were not reachable.
- The spread is wide: in SURMOUNT-1 at the 15 mg (trial dose, not a recommendation, PMID 35658024) dose, about 63% reached at least 20% loss while roughly 10% did not reach 10% (efficacy estimand, ClinicalTrials.gov NCT04184622).
- In the 160-person SURMOUNT-1 DXA substudy, roughly three quarters of the weight lost was fat (PMID 39996356). In the full trial, waist fell about 14.6 to 19.9 cm depending on dose (efficacy estimand, ClinicalTrials.gov NCT04184622).
- After stopping in SURMOUNT-4, the placebo-switch group regained about 14% over the next year while those who continued kept losing (treatment-regimen estimand, PMID 38078870).
- These are trial results, not a recommendation or a promise; tirzepatide is a prescription medicine and any decision belongs with a clinician.
Frequently asked questions
What is the average weight loss on tirzepatide before and after 72 weeks?+
In the SURMOUNT-1 obesity trial, at once-weekly doses of 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024), the average weight reduction from baseline to week 72 was about 15.0%, 19.5%, and 20.9% on the conservative treatment-regimen estimand, versus 3.1% on placebo (PMID 35658024). On the on-treatment efficacy estimand posted to ClinicalTrials.gov, the same doses averaged 16.0%, 21.4%, and 22.5%, versus 2.4% on placebo (efficacy estimand, ClinicalTrials.gov NCT04184622). These are trial averages, not a result guaranteed for any one person.
How fast does tirzepatide work week by week?+
No full weekly table of SURMOUNT-1 weight appears in the fetchable sources reviewed; the NEJM full text and appendix, one place such a table could sit, were not accessible. The FDA Medical Review (NDA 217806) describes separation from placebo as early as week 4. Per that review, the SURMOUNT-1 arms assigned 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) reached maintenance at weeks 4, 12, and 20, respectively, during a 20-week escalation. The reviewer describes weight falling until a plateau around week 60. ClinicalTrials.gov NCT04184622 provides the only tabulated intermediate point, week 20: the pooled SURMOUNT-1 arms assigned 10 mg (trial dose, not a recommendation, PMID 35658024) and 15 mg (trial dose, not a recommendation, PMID 35658024) were down about 13.2 kg (least-squares mean, efficacy estimand, ClinicalTrials.gov NCT04184622) versus 2.5 kg on placebo (efficacy estimand, ClinicalTrials.gov NCT04184622).
How much of the weight lost is fat versus lean mass?+
In a DXA substudy of 160 SURMOUNT-1 participants, the pooled tirzepatide group lost about 33.9% of fat mass and 10.9% of lean mass by week 72, versus 8.2% and 2.6% on placebo (open-access DXA substudy, PMID 39996356). In both groups the loss was roughly three quarters fat and one quarter lean; tirzepatide simply produced far more total loss. In absolute terms, the open-access full text reports about 15.9 kg of fat and 5.6 kg of lean mass lost in the tirzepatide group (PMC11965027).
What happens to weight after stopping tirzepatide?+
SURMOUNT-4 tested that directly. After a 36-week lead-in in which people lost a mean of 20.9%, those switched to placebo regained about 14% of body weight over the next year while those who continued tirzepatide kept losing, a difference of 19.4 percentage points on the treatment-regimen estimand (PMID 38078870). By week 88, 89.5% of the continued group had kept at least 80% of their lead-in loss, versus 16.6% of the group that stopped (treatment-regimen estimand, PMID 38078870).
Why do individual before and after photos differ from the trial averages?+
Because the trial figures are averages with a wide spread around them. In SURMOUNT-1, at the 15 mg (trial dose, not a recommendation, PMID 35658024) dose, about 63% of people reached at least 20% loss on the efficacy estimand while more than a third did not (efficacy estimand, ClinicalTrials.gov NCT04184622). Dose, how long someone has been escalating, whether they stayed on the drug, and individual tolerability all move a single result away from the group mean. Weight lost in the SURMOUNT-1 DXA substudy was mostly fat rather than lean mass (PMID 39996356), and a photo captures shape rather than the number on a scale.
Does tirzepatide reduce waist size?+
In SURMOUNT-1, at the 5 mg (trial dose, not a recommendation, PMID 35658024), 10 mg (trial dose, not a recommendation, PMID 35658024), and 15 mg (trial dose, not a recommendation, PMID 35658024) doses, waist circumference fell by about 14.6 cm, 19.4 cm, and 19.9 cm at week 72, versus 3.4 cm on placebo (efficacy estimand, ClinicalTrials.gov NCT04184622). A DXA substudy measured a pooled waist reduction of about 18.1 cm from a baseline of 111.5 cm, reported in the open-access full text (PMC11965027). As with weight, these are averages, and an individual change can be larger or smaller.
Sources and references
- 1.Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med 2022;387(3):205-216. NCT04184622. PMID 35658024. PubMed PMID 35658024
- 2.SURMOUNT-1 posted results, ClinicalTrials.gov NCT04184622 (primary treatment period; efficacy-estimand values unless stated). Fetched 2026-09-29. clinicaltrials.gov / NCT04184622
- 3.Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes Obes Metab. 2025 May;27(5):2720-2729. Erratum in Diabetes Obes Metab. 2025 Nov;27(11):6823. Open-access DXA substudy. PMID 39996356. PMC11965027. PMC11965027 full text (PMID 39996356)
- 4.Aronne LJ, et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA 2024;331(1):38-48. NCT04660643. PMID 38078870. PubMed PMID 38078870
- 5.SURMOUNT-4 posted results, ClinicalTrials.gov NCT04660643 (efficacy-estimand values). Fetched 2026-09-29. clinicaltrials.gov / NCT04660643
- 6.Zepbound (tirzepatide) US prescribing information, Eli Lilly and Company, via the openFDA drug label API. SPL version 40, effective 2026-08-28. Fetched 2026-09-29. openFDA / Zepbound label
- 7.US FDA CDER Statistical Review, NDA 217806 (Zepbound / tirzepatide), Reference ID 5257062. Treatment-regimen estimand. Fetched 2026-09-29. fda.gov / NDA 217806 Statistical Review
- 8.US FDA CDER Clinical/Medical Review, NDA 217806 (Zepbound / tirzepatide), Reference ID 5274339. Fetched 2026-09-29. fda.gov / NDA 217806 Medical Review
Related reading
Tirzepatide: Full Profile
What it is, how it works, and what the trials measured
Tirzepatide vs Semaglutide
Comparison of tirzepatide and semaglutide
Retatrutide vs Tirzepatide
Comparison of retatrutide and tirzepatide
GLP-1 Side Effects
What the gastrointestinal effects look like and when they ease
Tirzepatide in Vietnam
Access, sourcing, and the local picture
Microdosing Tirzepatide
What is and is not known about lower doses
This guide is for educational purposes only and is not medical advice. It describes what published clinical trials, regulatory reviews, and drug labelling reported; it is not an endorsement, a recommendation, or an instruction to use any medicine. Tirzepatide is a prescription medicine, and weight-loss results vary between individuals. Consult a qualified healthcare professional before making any decision about your health.