Start with the treatment that was studied
A weight-loss percentage is easier to understand when the treatment period, comparison and participant group travel with it. STEP 1 is foundational evidence for weekly injectable semaglutide in adults with overweight or obesity without diabetes. It is also a useful example of why “what happened during treatment?” and “what happened after treatment?” need separate answers.
STEP 1 randomized 1,961 adults without diabetes, with BMI at least 30 or at least 27 with a weight-related condition. Participants received weekly subcutaneous semaglutide 2.4 mg or placebo for 68 weeks, both with lifestyle intervention. Novo Nordisk funded the trial.[1]
For a wider view of product status and study outcomes, read our peptides for weight loss overview.
Read the average without turning it into a promise
Mean weight change was −14.9% with semaglutide and −2.4% with placebo. The published estimated treatment difference was −12.4 percentage points. It need not equal a subtraction of rounded displayed means, which would give −12.5.
STEP 1: both groups received lifestyle intervention. Common zero baseline on a 0–20% scale.
For a hypothetical 200-pound starting weight, a 14.9% change is 29.8 pounds. This is only a translation of a percentage into familiar units. It does not tell a reader how quickly change would occur, whether they would reach the average, or whether they could tolerate the treatment. Trial averages describe a group, including variation that a single headline cannot show.
The primary analysis assessed treatment effects regardless of discontinuation or rescue interventions. Nausea and diarrhea were common; gastrointestinal events led to discontinuation in 4.5% with semaglutide versus 0.8% with placebo. Efficacy and continuation therefore deserve attention together.
For a direct medication comparison, read SURMOUNT-5. Keep the longer treatment horizon beside the cost with our quote comparison tool.
The extension is a different view of the evidence
The exploratory STEP 1 extension followed 327 participants for a year after both study treatment and lifestyle intervention stopped. In the prior semaglutide group, mean loss at week 68 was 17.3%; participants regained 11.6 percentage points by week 120, leaving a reported net loss of 5.6% from baseline.[2]
| Feature | Original STEP 1 | Off-treatment extension |
|---|---|---|
| Population analyzed | 1,961 randomized adults | 327 participants in the extension |
| Question | Weight change during assigned treatment | Change after treatment and lifestyle support ended |
| Time point | Week 68 | Week 120 |
| How to read it | Randomized comparison | Exploratory follow-up of a subset |
The extension’s 17.3% figure is not a correction of the original trial’s 14.9%. It describes the extension subset. Combining the two into a single before-and-after line would silently change the group being followed. The same care is needed whenever a follow-up report includes only part of the original cohort.
What stopping tells us—and what it does not
The extension suggests that maintaining a treatment-associated change deserves planning beyond the initial prescription. It does not establish that every person will regain the same amount. Because lifestyle support also ended, the observed course cannot isolate withdrawal of the medicine from every other change in the study setting. Nor did this extension test a particular tapering plan or a switch to another treatment.
That is why the useful takeaway is a question about continuity, not a self-directed stopping schedule. Ask your clinician how progress will be reviewed, what would prompt a change, and how a longer-term plan would be managed. If access or affordability becomes difficult, bring that concern into the clinical conversation early rather than relying on a headline to guide dosing decisions.
It is also worth distinguishing treatment duration from subscription duration. A clinical plan may be ongoing while a commercial contract is billed monthly, prepaid or renewed on a separate schedule. Neither arrangement, by itself, establishes what length of treatment is right for a patient. The agreement should explain the financial obligation without pretending to answer the medical question.
Use maintenance evidence to ask better service questions
A provider comparison should examine what happens after enrollment: follow-up access, prescription handoffs, renewal charges and the process for changing or leaving a service. Our short-commitment shortlist concerns payment flexibility, not a recommendation for short treatment. The WeightWatchers Clinic review provides one service model to examine alongside those questions.
For costs, request a quote that distinguishes the first payment from recurring charges. Use the quote comparison tool to compare the same coverage period and keep missing amounts visible. A planned follow-up conversation and a clear written renewal are more informative than treating a 68-week trial result as a guarantee attached to a membership.