Losing weight can be challenging, and for many people, prescription medications offer extra help in reaching their goals.
However, new research shows that stopping these medications may lead to gaining weight back.
A recent meta-analysis, published in BMC Medicine, reviewed data from 11 clinical trials and found that many patients regained some of the weight they had lost after they stopped taking weight loss drugs.
While the exact amount of weight regain differed depending on the medication, the overall pattern was clear: weight often comes back after treatment ends.
In the United States, six anti-obesity medications have been approved by the Food and Drug Administration (FDA) to help people lose weight. These include orlistat, phentermine-topiramate, and semaglutide.
Another type of drug, called glucagon-like peptide-1 (GLP-1), was originally developed for diabetes but is now commonly prescribed for weight loss.
These medications can help people lose a significant amount of weight, especially when combined with healthy eating and exercise. However, recent studies have found that once patients stop taking them, some of the lost weight often returns.
Researchers Xiaoling Cai, Linong Ji, and their team studied 1,574 people who had been taking weight loss medications and 893 people in control groups. They looked at weight changes after the medications were stopped, measuring both body weight and body mass index (BMI).
Among the 11 studies analyzed, six focused on GLP-1 receptor agonists, one on GLP-1 and GLP dual receptor agonists, one on orlistat, two on phentermine-topiramate, and one on naltrexone-bupropion.
The researchers considered different factors that could affect weight regain, such as the type of medication, whether the person had diabetes, and whether they followed lifestyle changes like diet or exercise.
Their findings showed that weight loss during treatment was clear and measurable, but once the medication stopped, weight regain began as early as eight weeks later. On average, weight continued to increase for about 20 weeks before leveling off. Participants experienced noticeable regain at eight, 12, and 20 weeks after stopping treatment.
The amount of weight regained varied. For example, people who took tirzepatide, a GLP-1 drug, for 36 weeks and then switched to a placebo gained back almost half of the weight they had lost.
The study did not include weight loss approaches like lifestyle changes or bariatric surgery, so direct comparisons between different weight loss strategies could not be made. However, the researchers noted that weight regain is not unique to medications.
It has also been seen after surgical weight loss procedures such as gastric bypass and vertical banded gastroplasty. This suggests that keeping weight off is an ongoing challenge, regardless of how the weight is lost.
This study highlights an important reality about weight management: medications can help with weight loss, but the benefits may fade if treatment is stopped. The body often works to return to its previous weight, a process influenced by biological and behavioral factors.
This rebound effect means that weight management needs long-term planning and support. Patients may need ongoing treatment, whether that means continuing medication, making lasting changes to diet and exercise, or a combination of strategies.
Doctors and patients should discuss these possibilities before starting weight loss medications so that expectations are realistic and maintenance plans are in place. Ultimately, successful long-term weight control is about building healthy habits and having strategies to prevent regain.
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The study is published in BMC Medicine.
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