The STEP 1 extension addresses a practical question that the original weight-loss trial could not answer: what happened after treatment ended? Among 327 participants included in the extension analyses, those previously assigned semaglutide regained about two-thirds of their earlier average weight loss during the following year. They nevertheless remained, on average, below their starting weight. Both findings belong in the interpretation; neither universal regain nor permanent maintenance describes the results.
For someone assessing the financial commitment of obesity treatment, the central lesson concerns time horizons. A price covering an initial treatment period does not establish what maintaining its benefits will require. But the extension did not measure affordability, insurance interruptions, subscription contracts, or lifetime treatment costs. This article separates its clinical evidence from editorial budgeting implications, using the supplied extension full text, indexed primary-report abstracts for the other trials, and available official FDA material—not an examination of every protocol or supplement.
At a glance
- Population
- The extension analysis included 327 treatment completers from selected sites, compared with 1,961 adults randomized in the original STEP 1 trial.
- What ended
- At week 68, both study medication and the trial’s structured lifestyle intervention stopped; follow-up continued to week 120.Sources: [2]
- Average weight trajectory
- The former semaglutide group lost 17.3% through week 68, regained 11.6 percentage points of baseline weight, and had a reported net loss of 5.6% at week 120.Sources: [2]
- Individual variation
- Among former semaglutide participants with onsite week-120 measurements, 95 of 197, or 48.2%, remained at least 5% below baseline weight.Sources: [2]
The original experiment tested treatment, not withdrawal
STEP 1 randomly assigned 1,961 adults without diabetes to once-weekly subcutaneous semaglutide or placebo in a 2:1 ratio. Eligibility required a body mass index of at least 30, or at least 27 with a weight-related condition. The semaglutide study arm targeted 2.4 mg and included 16 weeks of dose escalation within 68 weeks of treatment. These doses identify the experiment, not instructions for treatment.
Both groups also received structured lifestyle counseling. The original trial’s coprimary endpoints were percentage weight change and achieving at least 5% weight loss. Its main analysis sought to estimate assignment effects regardless of treatment discontinuation or additional weight-management interventions, rather than describing only people who successfully stayed on medication.
At week 68, estimated average weight change was −14.9% with semaglutide and −2.4% with placebo. The between-group difference was −12.4 percentage points, with a 95% confidence interval from −13.4 to −11.5. That interval describes uncertainty around an average treatment contrast; it is not a range of individual outcomes. Novo Nordisk funded STEP 1, including its extension.
The 327-person extension was a selected completer sample
The extension required participants to have completed the 68-week treatment period and consented to additional follow-up. Sites came from Canada, Germany, the United Kingdom, the United States, and Japan. In the latter two countries, sites were selected for high recruitment in the original trial. Of 333 people entering the extension, 327 attended at least one qualifying follow-up visit and entered its analysis set.
That set contained 228 former semaglutide participants and 99 former placebo participants—about one-sixth of the original randomized population. Their average age was 49 years, average weight 105.5 kilograms, and average BMI 37.6. About 67% were women and 75.8% were White. The authors found broadly similar starting characteristics to the original trial, but similarity does not remove selection associated with completing treatment.
The extension group also had larger initial semaglutide weight loss than the full trial: 17.3% versus 14.9%. Its estimated week-68 treatment difference was −15.3 percentage points, with a 95% confidence interval of −17.3 to −13.3. Consequently, the extension follows a somewhat more successful treatment experience, not an interchangeable sample of everyone who began STEP 1.
STUDY DATA · GLP-1 Care Ledger
STEP 1 extension: weight change from original baseline
Exploratory 327-person extension subset without diabetes. Weekly semaglutide 2.4 mg or placebo and structured lifestyle intervention ended at week 68; week 120 was one year later.
| Study group | Change from week 0 (%) |
|---|---|
| Semaglutide group, week 68 | -17.3 |
| Semaglutide group, week 120 | -5.6 |
| Placebo group, week 68 | -2 |
| Placebo group, week 120 | -0.1 |
Group names refer to the prior randomized assignment; neither group continued assigned treatment during the extension. These are selected-subset means, not all 1,961 STEP 1 participants. Medication and lifestyle support stopped together. Novo Nordisk funded the trial.
Original visualization of published aggregate data. No individual prediction or provider performance is represented. Original research ↗
Medication and organized support ended together
At week 68, participants stopped study medication and the structured lifestyle intervention. Researchers then followed them for another 52 weeks, through week 120. The extension was observational: participants were not newly randomized to continue semaglutide versus stop it. The former placebo group provided context, but there was no contemporaneous semaglutide-continuation arm.
This distinction limits causal separation. The results describe what followed withdrawal of a treatment package, not the isolated effect of stopping medication while holding organized support constant. Nor does ending trial counseling establish that participants abandoned their own dietary or physical-activity practices. Participation in outside lifestyle interventions was not recorded.
Other treatments were neither actively administered nor prohibited during follow-up. Investigator-reported weight-management medication use occurred in 9.2% of the former semaglutide group and 6.1% of the former placebo group. An analysis excluding these users showed a similar overall weight trajectory. That supports the main descriptive finding, but it does not turn an observational follow-up into a randomized test of different maintenance strategies.
Two-thirds regained is a ratio, not an individual forecast
During treatment, the extension’s semaglutide group lost an average of 17.3% of baseline weight. During follow-up, it regained 11.6 percentage points measured against baseline weight. Dividing 11.6 by 17.3 gives approximately 0.67: the basis for the two-thirds description. It does not mean that two-thirds of participants regained everything, or that everyone regained the same fraction.
A worked illustration makes the denominators clearer. For an illustrative starting weight of 100 units, a 17.3% loss leaves 82.7 units. Regaining 11.6 baseline-weight units brings weight to approximately 94.3 units. Relative to the lower, week-68 weight, that gain would be about 14%, not 11.6%. This is arithmetic illustrating the reported averages, not a participant record.
The study reported a net average loss of 5.6% at week 120. Subtracting rounded headline values gives 5.7%; rounding and the observed data contributing at different visits mean those summaries need not reconcile exactly. The placebo group lost 2.0% initially, regained 1.9 percentage points, and finished with a reported 0.1% net loss.
| Measurement | Former semaglutide group | Former placebo group |
|---|---|---|
| Average loss, baseline to week 68 | 17.3% | 2.0% |
| Average regain, week 68 to week 120 | 11.6 percentage points | 1.9 percentage points |
| Reported net loss, baseline to week 120 | 5.6% | 0.1% |
| At least 5% below baseline at week 120 | 48.2%: 95 of 197 measured | 22.6%: 21 of 93 measured |
Residual weight loss was real, but uneven
The average did not represent a uniform return to starting weight. At week 120, 48.2% of measured former semaglutide participants remained at least 5% below baseline, versus 22.6% of measured former placebo participants. These proportions describe people with final onsite measurements, not all original randomized participants or everyone who might stop treatment outside a trial.
Variation was substantial. The standard deviation of regain in the former semaglutide group was 7.7 percentage points; the standard deviation of net baseline-to-week-120 weight loss was 8.9%. A standard deviation measures spread among observations, unlike a confidence interval, which describes uncertainty in an estimated average. These figures cannot identify an individual’s future trajectory.
Exploratory analyses also found that participants with greater initial losses tended to regain more weight yet retain larger net losses. That apparent paradox is straightforward: a larger initial reduction leaves more room both for regain and for residual benefit. It does not establish a validated prediction rule. Follow-up ended after one year off treatment, so the study could not determine whether remaining weight loss would persist or eventually disappear.
Health markers moved back, but not all in lockstep
Most measured cardiometabolic improvements moved toward baseline after withdrawal. In the former semaglutide group, average systolic blood pressure went from 129 mm Hg at baseline to 121 at week 68 and 131 at week 120. Average HbA1c, a measure of longer-term blood glucose, moved from 5.7% to 5.2% and then 5.6%. Thus, blood pressure and glucose did not show identical residual patterns.
Some lipid and inflammatory measures retained improvement. Geometric mean triglycerides moved from 131.1 to 95.7 and then 122.4 mg/dL. C-reactive protein, an inflammation marker, moved from 2.95 to 1.28 and then 1.83 mg/L. HDL cholesterol remained above baseline. These observations argue against describing withdrawal as an instantaneous erasure of every measured change.
Among participants with prediabetes initially, 93.6% in the semaglutide group had normal-range HbA1c at week 68, compared with 43.3% at week 120. These observed categories are not proof of permanent diabetes prevention. The separate analysis of longer-term diabetes progression addresses a different question. STEP 1’s extension measured risk markers, not reductions in heart attacks, kidney failure, or deaths, and could not disentangle medication effects from weight-related mechanisms.
Missing measurements matter despite strong retention
Of the 333 people entering the extension, 312 completed it, a reported completion rate of 93.7%. However, final onsite measurements were available for 290 people: 197 in the former semaglutide group and 93 in the former placebo group. Another 22 completed final contact by telephone or email. Their self-reported measurements were not included in the onsite analyses.
COVID-19 disruptions contributed to alternative visits. High contact retention therefore did not mean complete measured weight data. If people missing onsite assessments had systematically different trajectories, observed averages could differ from what complete measurement would have shown. The supplied report does not establish the direction or size of any such effect.
All extension analyses were exploratory, with no sample-size power calculation and no formal significance testing for the off-treatment findings. Its principal regain summaries used observed data and standard deviations, not confidence intervals around a randomized withdrawal effect. The original treatment-phase confidence intervals should not be borrowed to make the later descriptive regain estimate appear more precise.
Safety and product identity remain separate questions
The original STEP 1 abstract reported nausea and diarrhea as the most common semaglutide adverse events, generally transient and mild to moderate. Gastrointestinal events nevertheless led 59 semaglutide participants, or 4.5%, to discontinue treatment, compared with five placebo participants, or 0.8%. Averages for successful completers should be read alongside this evidence that tolerability prevented some participants from continuing.
The extension did not systematically collect adverse events. It therefore cannot provide a comprehensive estimate of symptoms or medical problems after withdrawal, nor establish that stopping was harmless. Weight and laboratory follow-up answer different questions from structured adverse-event surveillance. The supplied evidence also does not support a general safety ranking between stopping and continuing indefinitely.
These findings concern the studied subcutaneous formulation and treatment setting. They do not automatically transfer to oral products, compounded preparations, or particular care providers. FDA states that compounded drugs are not FDA approved or reviewed before marketing for safety, effectiveness, or quality, and identifies dosing errors and semaglutide salt concerns. The guide to comparing compounded and approved prices separates price comparisons from unsupported equivalence assumptions.
Other maintenance trials answer different experiments
SURMOUNT-4 provides a randomized withdrawal comparison, but for tirzepatide rather than semaglutide. After 36 weeks of open-label weekly injections at maximum tolerated study doses of 10 or 15 mg, 670 participants were randomized to continue treatment or switch to placebo for 52 weeks, with diet and physical activity. Its primary endpoint began at randomization, not the original baseline.
From that point, mean weight changed by −5.5% with continued tirzepatide versus +14.0% with placebo; the estimated difference was −19.4 percentage points, with a 95% confidence interval of −21.2 to −17.7. Gastrointestinal events were most common and occurred more often with tirzepatide. As the SURMOUNT-4 design analysis explains, this directly tests continuation versus withdrawal in a selected lead-in population, not comparative superiority over STEP 1.
SURMOUNT-MAINTAIN, funded by Eli Lilly, tested another question: continuation, dose reduction, or placebo after 60 weeks of tirzepatide. At week 112, estimated baseline-relative losses were 21.9%, 16.6%, and 9.9%, respectively, with the confidence intervals shown below. Rescue treatment was permitted after specified regain, complicating a simple untreated-withdrawal interpretation. Gastrointestinal events predominated. These abstract-reported findings are not a semaglutide tapering protocol.
| Maintenance assignment | Estimated change from baseline at week 112 | Interpretive detail |
|---|---|---|
| Continue maximum tolerated 10 or 15 mg | −21.9% (95% CI −23.5 to −20.3) | Continued-treatment study arm |
| Reduce to 5 mg | −16.6% (95% CI −18.0 to −15.1) | Dose-reduction arm, not cessation |
| Switch to placebo | −9.9% (95% CI −11.1 to −8.8) | Rescue rules affect interpretation |
Budget for an uncertain horizon, not a promised endpoint
Editorial interpretation: the extension makes a short-course financial model incomplete if that model assumes all achieved loss will remain afterward. But it supplies no price, cost per maintained pound, economic benefit, or lifetime spending estimate. Its measured horizon was 68 weeks of treatment followed by 52 weeks off treatment—not decades of continued therapy.
A useful planning distinction is between the treatment horizon supported by evidence and the payment period in a written offer. Our budget workbook can organize quoted expenses without converting trial averages into personal predictions. The billing-cycle guide helps distinguish payment schedules from clinical duration. Neither a monthly bill nor a prepaid term establishes how long treatment will be beneficial, tolerable, affordable, or appropriate.
Contract questions remain documentary rather than biological. The Ro review is a place to check written membership and payment terms, not evidence that a provider offers the studied intervention or reproduces its outcomes. Scientifically, STEP 1 supports taking maintenance seriously; financially, it supports acknowledging uncertainty. It does not establish that everyone must purchase treatment indefinitely or that a particular commercial arrangement is worthwhile.
Questions & answers
Does two-thirds regained mean two-thirds of people regained all their weight?
No. It compares average regain with average earlier loss: 11.6 divided by 17.3 is approximately two-thirds. It is not a count of people returning to baseline. Among former semaglutide participants measured onsite at week 120, 48.2% remained at least 5% below starting weight. Neither statistic predicts an individual outcome.
Can the extension show how much regain was caused by ending lifestyle support?
No. Study medication and structured lifestyle support ended together, and outside lifestyle participation was not recorded. Without separately assigned withdrawal conditions, their contributions cannot be quantified. The extension documents the combined transition; it does not show that personal lifestyle efforts stopped or that support alone would have prevented regain.
Does this prove semaglutide must be used for life?
No. It supports the importance of maintenance treatment as a scientific question, but observed only one year after withdrawal in selected completers. It did not compare lifelong treatment with alternative strategies or identify who could maintain benefits without medication. Longer-term treatment decisions require evidence beyond this extension and individualized clinical assessment.
Do the tirzepatide studies establish a lower-dose semaglutide maintenance strategy?
No. SURMOUNT-MAINTAIN studied specified tirzepatide arms after a tirzepatide lead-in, with rescue rules and a different endpoint. SURMOUNT-4 also studied tirzepatide. They strengthen the broader evidence that continuation can affect maintenance, but do not validate semaglutide dose reduction, intermittent treatment, or a self-directed stopping schedule.
Can these results justify a provider’s long-term price?
Not by themselves. STEP 1 establishes clinical findings for its intervention and population, not the value of a membership, pharmacy arrangement, or compounded product. Evaluating a quote requires its actual terms and product identity. The trial did not measure affordability or show that paying more buys better maintenance outcomes.
Our assessment
The strongest supported conclusion is that substantial average regain followed withdrawal of semaglutide and structured lifestyle support in this selected STEP 1 completer cohort, while meaningful residual loss remained for many measured participants. Cardiometabolic markers generally weakened alongside that trajectory, but not uniformly. The extension is informative about what happened over one year; it is less decisive about isolated causes, individual prediction, alternative maintenance approaches, or lifelong need. Editorially, it argues for budgeting that acknowledges a potentially continuing care horizon—not for treating a subscription as a scientifically mandated lifetime purchase.
Sources & documentation
Scientific and official sources consulted October 20, 2026. Study findings apply to the populations, products and time periods described; they are not provider outcome data.
- Once-Weekly Semaglutide in Adults with Overweight or Obesity. ↗
- Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. ↗
- FDA concerns about unapproved GLP-1 drugs ↗
- Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. ↗
- Tirzepatide for maintenance of bodyweight reduction in people with obesity in the USA (SURMOUNT-MAINTAIN): a multicentre, double-blind, randomised, placebo-controlled trial. ↗