People who stop taking weight loss drugs regain all the weight they lost within a year, according to an analysis by the University of Oxford. The study, presented at the European Congress on Obesity, reviewed 11 studies involving 6,370 adults and found that patients typically lost 8kg on older GLP-1 drugs but returned to their original weight within 10 months of stopping.
For newer, higher-dose drugs such as Wegovy (semaglutide) and Mounjaro (tirzepatide), patients lost an average of 16kg but regained 9.6kg within a year, suggesting they would return to their starting weight in just over 20 months. The findings raise questions about long-term treatment, as NHS guidelines recommend weight loss injections for no more than two years.
Professor Susan Jebb, co-author of the study, noted that weight regain after stopping drugs is much faster than after dieting, where it takes at least five years to return to baseline. She highlighted the dilemma for the NHS: whether to invest in short-term treatment that leads to weight regain or accept these as lifelong therapies.
Experts stressed the need for behavioural support alongside medication. Tam Fry of the National Obesity Forum said users must improve their lifestyle, while Professor Jane Ogden called for psychological counselling and nutritional support after stopping injections. Jason Halford of the European Association for the Study of Obesity described weight loss jabs as an adjunct to behavioural change, not a replacement.
