The STEP-1 Extension
The clearest data on this is the extension of the STEP-1 trial. Participants lost about 17% of body weight over 68 weeks on semaglutide. After they stopped the peptide, they were followed for another year.
By the end of that year, they had regained about 12 of those 17 percentage points, leaving them about 6% below where they started. That's two-thirds of the original loss recovered.
The SURMOUNT-4 Comparison
For tirzepatide, the SURMOUNT-4 trial set up the same kind of comparison. People who switched to placebo regained about 14% of body weight over the following year. People who stayed on the peptide lost an additional 5.5%.
The body's setpoint, appetite signaling, and the lifestyle structure that the peptide had been smoothing all came back when the peptide was removed.
What this means
References2 sources
How to read these sources
This article uses primary sources and reviews to separate mechanism, human evidence, and context.
- Human Trial
Diabetes, Obesity and Metabolism
WileyWeight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension Read source
Used Here ForGrounding the weight-regain question in the STEP 1 extension, which followed weight after semaglutide was stopped.
Good ForHuman evidence on weight trajectory after treatment withdrawal.
Not ForPredicting an individual's personal weight-regain timeline.
Diabetes, Obesity and Metabolism 24(8):1553-1564 - Human Trial
American Medical AssociationContinued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial Read source
Used Here ForAdding the randomized tirzepatide withdrawal data from SURMOUNT-4.
Good ForHuman trial evidence comparing continued tirzepatide with switching to placebo.
Not ForPredicting an individual's personal weight-regain timeline.
JAMA 331(1):38-48