Study Finds Weight Regain After Stopping Weight-Loss Jabs Happens Within Two Years. People who stop taking weight-loss injections tend to regain all the weight they lost in under two years, according to a major new study. The research, led by academics at University of Oxford and published in BMJ, analysed 37 studies involving more than 9,300 participants. Weight-loss drugs known as GLP-1 agonists, originally developed to treat diabetes, helped participants lose an average of 8.3kg during treatment. After stopping medication, participants regained weight at an average rate of 0.4kg per month, returning to their original weight within about 1.7 years. The study found weight regain after stopping medication was almost four times faster than after behavioural programmes such as diet or exercise plans. Researchers said the rapid regain reflects obesity as a chronic, relapsing condition, rather than a failure of the medicines themselves. Health benefits linked to weight loss, including improvements in blood pressure and cholesterol, were also lost within around 1.4 years of stopping treatment. Experts and patient groups stressed that weight-loss drugs should be paired with long-term lifestyle and behavioural support to help people maintain results.