tirzepatide mastery course
Unit 7 of 12

Clinical Evidence: Weight Loss

up to 22.5% weight reduction -- the SURMOUNT program and head-to-head data vs semaglutide

Closing the Surgery Gap

The SURMOUNT program tested tirzepatide specifically for obesity and overweight in adults without diabetes. SURMOUNT-1 delivered the headline: 22.5% mean body-weight loss at the 15mg dose over 72 weeks, with more than a third of participants losing 25% or more. SURMOUNT-5 provided the first head-to-head comparison against semaglutide 2.4mg for weight management. This unit breaks down each trial, examines weight maintenance data, and evaluates what the body-composition evidence actually shows.

SURMOUNT Results

Explore weight-loss outcomes across the SURMOUNT trial program and compare dose-response curves.

interactive SURMOUNT trial chart
-22.5 kg
mean absolute weight loss with tirzepatide 15 mg at 72 weeks in surmount-1
47%
greater relative weight loss vs semaglutide 2.4 mg in surmount-5 (-20.2% vs -13.7%)
39%
of surmount-1 participants on 15 mg lost at least 20% of body weight
~14%
body weight regained over 52 weeks after stopping tirzepatide in surmount-4
chronic therapy, not a short course. SURMOUNT-4 demonstrated that stopping tirzepatide leads to approximately 14% weight regain over 52 weeks. Only 16.6% of patients switching to placebo maintained 80% of their weight loss. Patients should be counseled that ongoing treatment is needed to sustain results.

key terms for this unit

S surmount clinical program
The phase 3 clinical trial program that evaluated tirzepatide specifically for obesity and overweight in adults. SURMOUNT-1 was the pivotal trial; SURMOUNT-5 provided the head-to-head comparison against semaglutide 2.4 mg.
R responder rate clinical metric
The percentage of trial participants achieving a pre-defined threshold of weight loss (e.g., >=5%, >=10%, >=20%). In SURMOUNT-1, 91% achieved >=5% and 39% achieved >=20% at the 15 mg dose.
D dexa scanning measurement method
Dual-energy X-ray absorptiometry, the imaging technique used in the SURMOUNT-1 body composition substudy to quantify fat mass versus lean mass changes during treatment.
B bmi clinical metric
Body mass index, calculated as weight (kg) divided by height squared (m2). SURMOUNT-1 enrolled adults with BMI >=30 (obesity) or >=27 with at least one weight-related comorbidity.
R randomized withdrawal trial design
A trial design where all participants first receive the active drug, then are randomized to continue or switch to placebo. SURMOUNT-4 used this design to assess weight maintenance after initial weight loss.