Individuals who cease taking weight loss injections regain the weight they lost in less than two years, at a significantly accelerated pace compared to other weight management strategies, a major new analysis has concluded.
The Pace of Weight Regain After Medication
The research, spearheaded by academics at the University of Oxford and published in the BMJ, reviewed 37 existing studies involving 9,341 participants. It found that after stopping treatment with GLP-1 agonist drugs—medications like Wegovy and Mounjaro that mimic a fullness hormone—weight was regained at an average rate of 0.4kg per month.
During an average treatment period of 39 weeks, participants lost roughly 8.3kg. However, they regained 4.8kg within the first year of stopping. The analysis projects that, on average, people return to their pre-treatment weight within 1.7 years of ending any weight loss medication.
Not a 'Failing of the Medicines'
Dr Sam West from Oxford's Nuffield Department of Primary Care Health Sciences emphasised that the rapid rebound is not a flaw in the drugs themselves. "These medicines are transforming obesity treatment and can achieve important weight loss," he stated.
"However, our research shows that people tend to regain weight rapidly after stopping – faster than we see with behavioural programmes," Dr West added. "This isn’t a failing of the medicines – it reflects the nature of obesity as a chronic, relapsing condition."
The rate of weight regain after stopping medication was found to be almost four times faster than after completing behavioural programmes involving diet and exercise plans.
Health Benefits Also Reversed
The study also delivered crucial findings regarding broader health metrics. The positive effects these drugs have on cardio-metabolic markers, such as blood pressure and cholesterol, dissipated after stopping treatment. These benefits returned to baseline levels within approximately 1.4 years.
Experts stress that the findings underscore the need for a sustained, multi-faceted approach. Dr Faye Riley, Research Communications Lead at Diabetes UK, commented: "Weight loss drugs can be effective tools... but this research reinforces that they are not a quick fix."
She advocated for "tailored wraparound support alongside them, to ensure people can fully benefit and maintain weight loss for as long as possible." This sentiment was echoed by Katharine Jenner of the Obesity Health Alliance, who pointed to the role of the wider food environment in making sustained weight loss challenging.
An NHS spokesperson reiterated that while these treatments are a valuable new tool, they "must be paired with behavioural and lifestyle wraparound support including advice on healthier diets and physical activity to keep the weight off in the long term." The health service is expanding its digital weight management programme to support more people annually.
