The main finding
In one sentence: One year after semaglutide and lifestyle support ended, people who had taken the medicine had regained 11.6 percentage points of body weight, about two-thirds of what they had lost, leaving a net loss of 5.6% from where they started.
Group averages, not an individual prediction. A trial result describes what happened to a defined group over a defined time.
On this page
Why this study matters
STEP 1 was the main trial of semaglutide (Wegovy, Ozempic) 2.4 mg for weight in adults without diabetes. This follow-up asked what happened to a subset of those participants after the trial ended and all treatment stopped. It is one of the few studies that tracked people for a full year off the medicine. Canadian sites took part, which makes it directly relevant to readers here.
Who was in the study
STEP 1 originally randomized 1961 adults with a body mass index, or BMI, of 30 or more, or 27 or more with at least one weight-related health condition. BMI is a number that relates weight to height. People with diabetes were not included.
The extension followed 327 people who had completed the full 68 weeks. The authors describe this as a representative subset. It included all eligible participants from every site in Canada, Germany and the United Kingdom, plus the sites in the United States and Japan that had recruited the most people. Follow-up ran for a further year, to week 120 from the original start.
What the researchers did
In the main trial, people were randomized, meaning assigned by chance, to weekly injections of semaglutide 2.4 mg or a placebo for 68 weeks. A placebo is an injection that looks the same but contains no medicine. The dose was raised over the first 16 weeks. Both groups also received lifestyle support.
At week 68, everything stopped: the medicine, the placebo and the lifestyle support. The extension then measured weight and heart and metabolic risk factors one year later. All of the extension analyses were exploratory, which means they were not the trial's main planned tests and were based on the data that happened to be observed. No estimand was specified for the extension. An estimand is a precise statement of what a trial is trying to measure and how missing data are handled.
What they found
From week 0 to week 68, the semaglutide group had lost an average of 17.3% of body weight, and the placebo group 2.0%.
By week 120, one year after stopping, the semaglutide group had regained 11.6 percentage points of body weight, and the placebo group 1.9 percentage points (R32-C25). This left a net change from the original starting weight of -5.6% in the semaglutide group and -0.1% in the placebo group.
| Group | Week 0 to 68 | Regain, week 68 to 120 | Net change, week 0 to 120 |
|---|---|---|---|
| Semaglutide 2.4 mg | -17.3% | +11.6 percentage points | -5.6% |
| Placebo | -2.0% | +1.9 percentage points | -0.1% |
The authors summarize this as participants regaining about two-thirds of their prior weight loss (R32-C26). The improvements in heart and metabolic risk factors seen at week 68 with semaglutide moved back toward their starting values for most measures by week 120. The published summary we reviewed does not report a between-group difference with a confidence interval for the extension period.
Side effects and people who stopped
This was an off-treatment follow-up, so no one was taking the study medicine. The published summary we reviewed does not report adverse events or the number of people who left the extension.
What this study does not tell you
- The 327 people were a selected subset of those who completed the full 68 weeks. People who stopped early are not represented.
- The analyses were exploratory and used observed data only, so the numbers are descriptive rather than a formal test.
- The medicine and the lifestyle support stopped at the same time. The study cannot separate the effect of losing one from the effect of losing the other.
- People with diabetes were not included, and follow-up covered one year off treatment, not longer.
- Several authors were employed by the manufacturer, Novo Nordisk, and some held company stock. Other authors reported advisory or research relationships with industry.
- Results from this study should not be lined up against stopping studies of other medicines, because the designs differ.
What it means in Canada
This extension included Canadian participants and shows that, in this group, most of the weight came back within a year of stopping both the medicine and lifestyle support. It supports the view that obesity behaves as a chronic condition. It does not describe how the medicine is prescribed or paid for in Canada. See semaglutide in Canada, public drug coverage by province and compare services for those questions.
Common questions
How much weight came back a year after stopping semaglutide in STEP 1?
People who had taken semaglutide regained 11.6 percentage points of body weight in the year after treatment ended, leaving a net loss of 5.6% from their starting weight.
What fraction of the weight loss was regained after stopping semaglutide?
The authors report that participants regained about two-thirds of their prior weight loss one year after semaglutide and lifestyle support were withdrawn.
Were Canadian sites part of the STEP 1 extension?
Yes. The extension included all eligible participants from sites in Canada, Germany and the United Kingdom, plus selected sites in the United States and Japan.
Related reading
Other studies in this library that bear on the same question.
STEP 1: semaglutide for weight loss in adults
What happens to weight when semaglutide is stopped: STEP 4
What happens to weight when tirzepatide is stopped: SURMOUNT-4
One year after stopping liraglutide or exercise: S-LiTE
Stopping and restarting GLP-1 medicines: a US cohort
Source
Original paper: John P H Wilding, STEP 1 off-treatment extension, Diabetes, obesity & metabolism, 2022. PubMed: https://pubmed.ncbi.nlm.nih.gov/35441470/. DOI: https://doi.org/10.1111/dom.14725. Funding: The summary we reviewed does not state the funding source, although several authors were employees of Novo Nordisk. How we summarized it: full text and extracted data.
This page explains a published study. It is not medical advice and does not describe whether a medicine is right for you. Talk to your doctor, nurse practitioner or pharmacist about your own situation. Reviewed and signed by two pharmacists registered in British Columbia, 2026-09-18.
Evidence records behind this page
Each record is a row in the clinical evidence file, taken from the published paper named above. The caution column is the limit the researcher recorded for that number.
This table scrolls sideways.
| Record | What the paper reports | Type | Population | Caution | Source |
|---|---|---|---|---|---|
| R32-C25 | In the STEP 1 extension, participants previously receiving semaglutide regained 11.6 percentage points of body weight during the year after treatment stopped, leaving a mean net loss of 5.6% from their original weight. | direct evidence | Adults with overweight/obesity without diabetes who completed STEP 1 | Selected completer subset; exploratory observed-data analysis; medication and lifestyle support stopped together, so their withdrawal effects cannot be separated. | PubMed 35441470 |
| R32-C26 | STEP 1 extension participants regained about two-thirds of their prior weight loss after semaglutide and lifestyle support ended; this was an exploratory follow-up of a selected trial subset. | direct evidence | Adults with overweight/obesity without diabetes who completed STEP 1 | Selected completer subset; exploratory observed-data analysis; medication and lifestyle support stopped together, so their withdrawal effects cannot be separated. | PubMed 35441470 |