STEP-4 (JAMA 2021) randomized 803 adults who completed semaglutide titration to continue or switch to placebo. Continued semaglutide: 7.9% additional loss. Placebo switch: 6.9% regain. 14.8 percentage-point gap quantifies the cost of discontinuation.
STEP-4, published in JAMA in 2021, used a randomized withdrawal design to quantify what happens when semaglutide is discontinued versus continued in patients who have already lost weight. After 20 weeks of open-label semaglutide titration during which all participants lost approximately 10.6%, 803 participants were randomized to continue semaglutide or switch to placebo for 48 weeks. Continued semaglutide produced 7.9% additional weight loss; placebo-switched participants regained 6.9% — a 14.8 percentage-point difference¹.
Trial design
STEP-4 (Rubino et al., JAMA 2021) was a 68-week randomized withdrawal trial in 803 adults with overweight or obesity without diabetes¹. Phase 1 (weeks 1-20): all 902 enrolled received open-label semaglutide titrated to 2.4 mg with lifestyle intervention. Phase 2 (weeks 20-68): 803 participants on 2.4 mg were randomized 2:1 to continue semaglutide 2.4 mg or switch to placebo, with continued lifestyle intervention. Primary endpoint: % weight change from week 20 to week 68.
Run-in weight loss
During the 20-week run-in, all participants lost a mean 10.6% — consistent with semaglutide 2.4 mg trajectory during the titration phase¹. 803 completed to the 2.4 mg dose and were eligible for randomization.
Primary outcome
From week 20 to week 68, continued semaglutide lost an additional 7.9% (total 17.4% from original baseline). Placebo-switched regained 6.9% (ending at 5.0% loss from baseline). Treatment difference -14.8 percentage points (95% CI -16.0 to -13.5; P<0.001)¹. Proportion ≥5% weight loss from original baseline at week 68: 88.7% continued vs 47.6% placebo-switched. Cardiometabolic outcomes followed the same pattern.
Regain trajectory
Weight regain in the placebo arm was approximately linear over 48 weeks, with most regain in the first 24 weeks. By the end of the 48-week post-randomization period, participants were still below pre-treatment baseline but had lost most of the additional benefit gained during run-in¹. The trajectory mirrors STEP-1 extension findings².
Clinical implications
STEP-4 crystallized obesity pharmacotherapy as long-term therapy. The randomized within-trial comparison eliminated confounding by indication that limits observational discontinuation studies. The conclusion: stopping semaglutide is associated with substantial weight regain even with continued lifestyle intervention.
STEP-4 supports counseling patients at therapy start that semaglutide is intended for chronic use, with discontinuation expected to result in weight regain. Patients should partner in deciding long-term therapy versus eventual structured taper, with full transparency about the data.
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Based on STEP-4 and STEP-1 extension, approximately two-thirds of weight lost will return over 12 months even with continued lifestyle intervention.
Lower dose for maintenance?
Reduced maintenance doses (e.g., 1.0 mg or 1.7 mg) are an active area of research. Randomized data specifically supporting this strategy are emerging.
Is the regain just water weight?
No. Regain reflected genuine increase in body fat and body mass. Cardiometabolic improvements partially reverted in parallel.
How long should I plan to take semaglutide?
Guidelines and trial data support indefinite use as long as tolerated and clinically appropriate. Obesity is framed as a chronic disease analogous to hypertension.
Way to keep weight off without continuing medication?
Without medication, full weight loss requires sustained behavioral effort exceeding pre-treatment baselines. Bariatric surgery is the most durable non-pharmacologic intervention. Most patients regain substantial weight after discontinuation.
References
Rubino D, Abrahamsson N, Davies M, et al.Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance: STEP 4.JAMA. 2021;325(14):1414-1425.PMID: 33755728
Wilding JPH, Batterham RL, Davies M, et al.Weight regain and cardiometabolic effects after withdrawal of semaglutide: STEP 1 extension.Diabetes Obes Metab. 2022;24(8):1553-1564.PMID: 35441470
Aronne LJ, Sattar N, Horn DB, et al.Continued Treatment With Tirzepatide for Maintenance of Weight Reduction: SURMOUNT-4.JAMA. 2024;331(1):38-48.PMID: 38078870
U.S. Food and Drug Administration.Wegovy (semaglutide) injection — Prescribing Information.FDA Drug Approval Records.View source
Citations are peer-reviewed where available. PubMed (PMID) links resolve to NCBI's PubMed. FDA links resolve to fda.gov. All citations were last verified 2026-05-11.
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