The sustainability of weight-loss drugs is under scrutiny as new research shows that people who stop taking glucagon-like peptide-1 (GLP-1) agonists regain the pounds at a steady rate, returning to their original size after around 1.7 years. The findings raise questions about whether this “magic cure” for obesity is actually unsustainable without a life-long commitment to the medication.
University of Oxford researchers assessed a range of clinical trials as well as Medline, Embase, PsycINFO, CINAHL, Cochrane and Web of Science databases, with a focus on what happened after cessation of treatment regarding adults who were overweight or obese. They found that, on average, people regained 0.4 kg (0.88 lb) per month, with all weight loss reversed after 1.7 years. What’s more, this gain was more rapid than seen in other dietary weight-loss interventions.
The study pooled data from 37 clinical trials and observational studies involving a total of 9,341 adults, making it one of the most comprehensive attempts so far to quantify what actually happens after people come off these medications. And weight gain wasn’t the only issue, as the rebound also negated the positive impact GLP-1 medications had on heart and metabolic health markers, including cholesterol and blood pressure. These cardiometabolic markers (including HbA1c, fasting glucose, cholesterol, triglycerides and blood pressure) returned to baseline even earlier than weight, at around 1.4 years after stopping treatment.
“GLP-1 receptor agonists should not be relied on as a magic cure for treating obesity,” said Qi Sun, an associate professor of medicine at Harvard Medical School. “While considerable weight loss, even if temporary, may still bring some health benefits for those with obesity, people using GLP-1 receptor agonists should be aware of the high discontinuation rate and the consequences of cessation of medications.”
While there’s no doubt that GLP-1 drugs like semaglutide and tirzepatide have transformed how we treat obesity, it’s worth noting that around half of users stop taking the medication within 12 months, having achieved their weight-loss goals. But this research provides strong evidence that short-term use – much like extreme calorie-restriction diets – delivers short-term results.
And, as the researchers add, the study isn’t to frame GLP-1 medications as a waste of time and money, but that users should keep in mind that they need a more holistic approach to weight loss that can help sustain the results they get while taking the drugs.
“This evidence suggests that despite their success in achieving initial weight loss, these drugs alone may not be sufficient for long term weight control,” they wrote. “This evidence cautions against short term use of weight management medications, emphasizes the need for further research into cost effective strategies for long term weight control, and reinforces the importance of primary prevention.”
The team acknowledge the limitations of their findings, which include assessing studies that varied in design, length and quality, however, they used three different methods to analyze the data and each result provided a similar number in terms of when weight was regained after stopping medication.
While GLP-1 drugs have been around for more than a decade, 2024 saw a 700% increase in the number of Americans taking the medications for weight loss. In August 2025, researchers found that 12% of US adults have tried a GLP-1 drug to manage their weight – with a fifth being women aged 50 to 64 years, when menopausal hormonal shifts make it much harder to lose pounds by diet and exercise alone. (This alone is a topic worthy of much more research, with weight gain in women over the age of 50 years – which greatly increases their cardiometabolic health risks – traditionally viewed by medical scientists as just an inevitable part of the aging process.)
This new study, however, shines a light on how GLP-1 medications can lead to people putting more importance on drug intervention than nutrition, diet and physical activity for weight management – all things crucial for long-term cardiometabolic health.
“The study findings casted doubt on the notion that GLP-1 receptor agonists are a perfect cure for obesity,” said Sun. “Healthy dietary and lifestyle practices should remain the foundation for obesity treatment and management, with medications such as GLP-1 receptor agonists used as adjuncts.
“Such practises not only help prevent excess weight gain but can also lead to numerous health benefits that go beyond weight control,” the scientist added. “Effective public health measures, such as taxation on sugary beverages, clear food labeling, and subsidies for fresh fruit and vegetables, should be in place to facilitate the adherence and improvement of diet quality.”
In addition to this, we still don’t have a lot of data relating to long-term GLP-1 use and potential health issues, with the class of drugs being relatively new and not yet enough longitudinal research. This sort of data takes decades, if not longer, to gather.
With the GLP-1 discontinuation rate high among adults who are overweight or obese – one 2025 study of 125,474 individuals found that 46.5% of patients stopped taking the medication after a year – the researchers call for more work to support people in managing their weight long-term.
The study was published in the journal The BMJ.
Source: University of Oxford via Scimex
