Anti-obesity medications can lead to dramatic weight loss—but what happens after patients stop taking them? Two recent studies shed light on the answer, revealing that while weight regain is common, some individuals maintain significant benefits well beyond treatment.
A global meta-analysis published in BMC Medicine examined data from 11 randomized controlled trials across six anti-obesity medications, including semaglutide, orlistat, and tirzepatide. Researchers found that most patients began regaining weight as early as eight weeks after discontinuing treatment, with weight gain continuing for up to 20 weeks before leveling off.
Yet new research from China suggests this isn’t always the case.
What the Global Data Shows
Led by Xiaoling Cai and Linong Ji, the meta-analysis reviewed outcomes from 1,574 treatment participants and 893 controls. Medications studied included:
- GLP-1 receptor agonists (e.g., semaglutide)
- Dual GLP/GIP agonists (e.g., tirzepatide)
- Other AOMs like orlistat and phentermine-topiramate
After discontinuation, most participants saw measurable weight regain by the 8-, 12-, and 20-week marks. For example, individuals who completed a 36-week course of tirzepatide regained nearly half their lost weight after switching to a placebo. However, the degree of rebound varied based on the specific drug, presence of diabetes, and adherence to lifestyle changes like diet and exercise.
The authors emphasized that this trend is not unique to medications. “Weight regain has also been observed after bariatric procedures like gastric bypass,” they noted, underscoring the challenge of long-term weight maintenance.
Durable Results in China’s SURMOUNT-CN Trial
In contrast, an observational study from Fudan University published in Life Metabolism followed 152 Chinese adults who completed a 52-week tirzepatide regimen and then stopped treatment. For another 26 weeks, participants received no additional medication or surgery.
Despite stopping therapy, participants maintained an average weight loss of 8.7% to 10.6% from baseline—far higher than the placebo group’s 2.5%. Waistlines shrank by over 10 centimeters on average, and metabolic health markers like HbA1c and LDL cholesterol continued to trend in a favorable direction.
This study marks the first real-world evidence of sustained weight loss after tirzepatide cessation in a Chinese population, providing a critical counterpoint to concerns about universal rebound.
Why Some Keep It Off
What accounts for the difference? The answer may lie in the intensity and duration of treatment, the specific drug mechanism, or population-specific physiology. The SURMOUNT-CN trial used high doses of tirzepatide over a full year, which may have contributed to more durable changes in appetite regulation and metabolism.
Still, both studies converge on a key point: for most people, weight loss is not a one-time fix. Long-term success likely depends on continued lifestyle support, behavioral interventions, and realistic expectations about what happens when medications end.
Journal References:
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- BMC Medicine, DOI: 10.1186/s12916-025-04200-0
- Life Metabolism, DOI: 10.1093/lifemeta/loaf024