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Anti-obesity drugs linked to weight regain after treatment ends
Last reviewed: 27.07.2025
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Patients prescribed weight-loss drugs may experience weight gain after stopping the medication, a meta-analysis published in BMC Medicine has found.
A study that analysed data from patients taking weight-loss drugs in 11 randomised trials shows that while the degree of weight return varies depending on the specific drug, there is an overall trend for weight gain after treatment ends.
Six anti-obesity drugs (AOMs) are approved by the U.S. Food and Drug Administration (FDA) to aid in weight loss, including orlistat, phentermine-topiramate, and semaglutide. Glucagon-like peptide-1 (GLP-1), a therapeutic originally developed to treat diabetes, is also increasingly being prescribed to patients for weight loss. However, recent studies have shown that patients prescribed AOMs may gain weight for several months after stopping these drugs.
Xiaoling Cai, Linong Ji, and colleagues conducted a meta-analysis of 11 studies from around the world that examined changes in body weight in patients after stopping AOM.
Overall, the authors analyzed data from 1,574 participants in the treatment groups and 893 participants in the control groups. Changes in body weight were measured by body mass index (BMI) and body mass index (BMI) after drug withdrawal.
Of the 11 studies included in the meta-analysis, six were GLP-1 receptor agonists (RAs); one was both GLP-1 and dual Ras; one was orlistat; two were phentermine-topiramate; and one was naltrexone-bupropion.
The authors took into account various confounding factors, including the type of medication, the presence of diabetes, and compliance or noncompliance with lifestyle changes such as diet or physical activity.
Their analysis found that AOMs were associated with significant weight loss during their use, followed by weight regain beginning about eight weeks after stopping use and continuing for an average of 20 weeks before stabilizing.
Weight gain varied depending on the time of observation, with study participants showing significant periods of weight regain at 8, 12, and 20 weeks after stopping AOM.
The amount of weight regained depended on several factors, including the type of medication taken and consistency in lifestyle modifications. For example, participants who completed 36 weeks of treatment with tirzepatide (a commercially available GLP-1 RA) regained nearly half the weight they had previously lost after switching to placebo.
The authors note that the meta-analysis did not include studies on lifestyle changes and bariatric surgery, which reduces the ability to compare different weight loss methods in the context of this study.
They also point out that weight gain has also been observed with other weight loss procedures, such as gastric bypass and vertical banded gastroplasty.