Groundbreaking new research indicates that the popular weight loss injections Mounjaro and Wegovy may need to be continued indefinitely to keep obesity under control. The findings present a significant challenge for the almost two million British adults who have used the treatments in the past year, the vast majority of whom are funding the costly drugs privately.
The High Cost of Stopping Treatment
According to the study published in the British Medical Journal, approximately half of all users discontinue their treatment within the first year, often due to side effects or the substantial financial burden. The medication can cost individuals up to £300 per month, depending on the dose and specific drug.
The research reveals a stark reality for those who stop: it takes an average of just one and a half years for people to regain all the weight they had lost. Scientists note that weight is piled back on four times faster after quitting the jabs compared to stopping a conventional diet.
A Lifelong Biological Challenge
Professor Susan Jebb, an expert on diet and population health at the University of Oxford, explained the implications to Sky News. "Most people who are living with obesity, who have all that genetic and metabolic predisposition to gain weight, are going to need lifelong support of some kind," she stated.
She added that the key unanswered question is how to help people maintain weight loss, a process distinct from losing weight initially. Between 40% and 70% of obesity risk is determined by genetics, making long-term control particularly difficult.
Sam West, another Oxford researcher involved in the work, emphasised that the drugs are "incredibly effective" while taken but are not a permanent fix. "They're not a silver bullet... when you stop taking them, the weight regain occurs rapidly," he said. Experts theorise that powerful biological drivers of obesity are abruptly reactivated when the medication ceases.
One Patient's Story: The Rebound Effect
The personal impact of this cycle is illustrated by Rosie Parsons, who lost eight stone using Wegovy, dropping from 19.5 stone to just over 11 stone. When her weight loss plateaued, she questioned the value of spending around £175 a month.
After switching to the more potent Mounjaro, she found the gastrointestinal side effects intolerable. In the four months since stopping treatment, she has regained four stone—half of her total weight loss.
"I'm just trying to figure out what to do," she said, highlighting the dual pressures of treatment cost and rising living expenses. "It probably does mean that I'll need to be on those drugs for life. But it's how to afford that because I can't get treatment through the NHS." Without the injections, she finds debilitating sugar cravings return in the evening.
The research underscores a critical dilemma for public health: while breakthrough drugs offer powerful tools against obesity, their long-term use and accessibility, particularly on the NHS, remain unresolved issues for millions.
