Weight loss treatments like Ozempic, Wegovy or Mounjaro have revolutionized the management of obesity, with spectacular weight losses. But one question comes up among all patients: what happens to this lost weight after the injections stop? A team from Trinity College, University of Cambridge and a meta-analysis published in eClinicalMedicine analyzed the trajectory of recovery during the months following the end of treatment.
More than a billion people live with obesity worldwide, and losing 5 to 10% of weight already improves the risk of diabetes or cardiovascular disease. THE GLP-1 receptor agonists such as semaglutide or tirzepatide allow in clinical trials to lose 15 to 20% of the initial weight, but approximately half of the patients stop within the first year and three quarters after two years. However, recovery does not follow a simple return to the starting point.
What weight gain after stopping the medication?
Researchers reviewed 48 studies on these drugs, including 36 randomized trials. Six large trials, totaling 3,236 people followed for up to 52 weeks after stopping, were used to model the recovery curve. Under treatment, the loss ranged from 15 to 20% of the starting weight. After stopping, the weight increased quickly at first, then more slowly, following an exponential “recovery” curve.
Approximately one year from stopping 60% lost weight was regained. The model then predicts a plateau around 75.3% of the initial loss resumed around 60 weeks, i.e. a lasting loss of approximately 25% of what had been lost. For someone who had lost 20% of their weight, they would therefore remain around 5% less weight in the long term. Half of this recovery occurs in almost 23 weeks, and the profiles are similar for semaglutide, tirzepatide, and liraglutide.
The weight comes back quickly… but not completely
Medical student at the Faculty of Clinical Medicine and Trinity College at the University of Cambridge, Brajan Budini summarizes the mechanism: “Medications such as Ozempic and Wegovy act as curbs on our appetite, making us feel full sooner, which means we eat less and therefore lose weight. When people stop taking them, they essentially take their foot off the brake, and this can lead to rapid weight regain.”. Frequent stops, linked to digestive effects and cost, therefore expose you to this rebound.
The authors also put forward several reasons why not all the weight is regained. By reducing appetite, these treatments can anchor smaller portions and more balanced meals, which persist after stopping. They could also permanently modify certain hormones or the “set point” of appetite in the brain. Steven Luo, also a medical student at the School of Clinical Medicine and Trinity College, emphasizes support: “When stopping weight loss medications, physicians and patients should be aware of the potential for weight regain and consider ways to mitigate this risk. It is important that people receive advice on improving their diet and exercise, rather than relying solely on medication, as this can help them maintain good habits when they stop taking them.”.
Limitations of available data
Another point worries specialists: 40 to 60% of the weight lost under GLP-1 corresponds to lean mass, including muscle. “Our projections show that even if people regain most of the weight they lost, they still maintain some of the weight loss, but what we currently don’t know is whether the same proportion of lean mass is regained. If the weight regained is disproportionately fat, individuals’ fat-to-lean mass ratio could ultimately be worse than before, which could have detrimental consequences for their health.”warns Brajan Budini.
The researchers highlight several limitations to their study: the modeling is based on trials which did not go beyond 52 weeks after stopping and concerned patients who had lost at least 3 kg under treatment. Longer-term trajectories, the precise composition of the weight regained and the impact on blood pressure or blood sugar levels still largely remain to be documented.