Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension
Wilding JPH, Batterham RL, Davies M, Van Gaal LF, Kandler K, Konakli K, Lingvay I, McGowan BM, +6 more
Diabetes, Obesity and Metabolism (2022) · n=327
One year after stopping semaglutide, participants regained two-thirds of their lost weight (11.6 percentage points) — and cardiometabolic improvements reverted in parallel. The single most important paper for the discontinuation-rebound conversation.
The STEP 1 extension is the off-treatment follow-up to the pivotal STEP 1 trial and the empirical anchor for every modern claim about discontinuation rebound on the GLP-1 class. Of the 1,961 STEP 1 participants who completed the 68-week active-treatment phase (mean weight loss: 17.3% on semaglutide, 2.0% on placebo), 327 participants were followed for an additional 52 weeks off study drug to characterize what happens when treatment stops. The semaglutide group regained 11.6 percentage points of body weight (SD 7.7) over the 52-week off-treatment window — approximately two-thirds of the active-phase loss. The placebo group regained 1.9 percentage points (SD 4.8). At week 120, the net body-weight change from study baseline was -5.6% (SD 8.9) on the semaglutide arm and -0.1% (SD 5.8) on placebo. Cardiometabolic improvements observed during active treatment — in lipid profile, blood pressure, glycemic measures, and quality-of-life metrics — reverted toward baseline in parallel with the weight regain. The authors framed the result as confirming the chronicity of obesity and arguing that ongoing treatment is required to maintain the cardiometabolic benefits.
The 327-participant follow-up cohort is a subset of the full STEP 1 population and does not capture the trajectory of the 1,961-participant intent-to-treat group. Participants who did not enroll in the extension may differ systematically (in tolerability, satisfaction, or weight-loss success) from those who did. The 52-week off-treatment window is long enough to characterize the rebound trajectory but does not address whether the regain stabilizes or continues at longer horizons; the longest published follow-ups now extend to two-plus years off-treatment in some cohorts and suggest plateau rather than continued regain, but the data quality there is uneven. The "two-thirds regain" framing has become the headline number for the GLP-1 class as a whole and is approximately accurate for semaglutide; tirzepatide, retatrutide, and the broader dual/triple-agonist class have not yet generated comparable off-treatment follow-up evidence at scale. Industry sponsorship by Novo Nordisk is disclosed.