People tend to regain weight more rapidly after stopping weight-loss drugs than after ending behavioural weight-loss programmes, according to new NIHR-funded research led by University of Oxford researchers, including ARC OxTV Theme 1 lead Professor Susan Jebb.
The systematic review and meta-analysis, published in The BMJ, analysed 37 studies including more than 9,000 adults. It found that weight increased by an average of 0.4 kg per month after stopping weight management medicines – a rate that would see people return to their starting weight within around 18 months.
For newer medicines such as semaglutide and tirzepatide, regain was even faster at 0.8 kg per month.
Crucially, the research found that weight regain after stopping drugs was approximately 0.3 kg per month faster than after ending behavioural programmes such as diet and exercise support – regardless of how much weight was initially lost.
Professor Jebb, who leads ARC OxTV's health behaviours research theme, said: "Obesity is a chronic, relapsing condition, not a short-term problem with a quick fix. When people lose weight through changes to their diet and activity, they're practising the skills that help maintain that loss. It may be that with medication, the weight comes off without necessarily developing those skills.
"These findings underscore the need for a more holistic and long-term approach to weight management, and increased emphasis on the importance of primary prevention of weight gain."
The findings come as real-world data shows around half of people discontinue GLP-1 receptor agonist treatment within 12 months, and just months after NICE published quality standards recommending post-treatment support for at least one year. An estimated nine in ten people currently using weight-loss medicines in the UK are purchasing them privately, often without the comprehensive clinical oversight and behavioural support that accompanies NHS prescribing.
Lead author Dr Sam West, postdoctoral researcher at the Nuffield Department of Primary Care Health Sciences, said: "These medicines are transforming obesity treatment and can achieve important weight loss. However, our analysis shows that people tend to regain weight rapidly after stopping – faster than we see with behavioural programmes. This isn't a failing of the medicines – it reflects the nature of obesity as a chronic, relapsing condition."
Associate Professor Dimitrios Koutoukidis, joint senior author, noted that the faster regain could be because people using drugs don't need to consciously practise changing their diet to lose weight. "When they stop taking the medication they might not have developed the practical strategies that could help them keep it off," he said.
The research was funded by the NIHR Oxford Biomedical Research Centre. This work aligns with ARC OxTV's broader portfolio of obesity and weight management research, which has informed national programmes including the NHS Diabetes Prevention Programme and NHS Digital Weight Management Programme.
Full citation: West S, Scragg J, Aveyard P, Oke JL, Willis L, Haffner SJP, Knight H, Wang D, Morrow S, Heath L, Jebb SA, Koutoukidis DA. Weight regain following the cessation of medication for weight management: a systematic review and meta-analysis. BMJ, 2026. DOI: 10.1136/bmj-2025-085304