Patients May Require Lifelong Use of Weight-Loss Injections

A significant study conducted by researchers at Oxford University indicates that individuals using weight-loss injections like Ozempic, Mounjaro, and Wegovy may need to continue these treatments indefinitely. The research highlights a trend where users regain weight much faster than traditional dieters after discontinuing their medication, with many regaining the lost weight within two years.

The comprehensive review analyzed 37 studies involving over 9,300 participants and uncovered that once patients cease treatment, they typically regain approximately one pound per month. This rapid weight gain, dubbed the “Ozempic rebound,” raises concerns about the long-term implications of these medications. Researchers noted that individuals who stop using these injections could find themselves back at their pre-treatment weight within 17 to 20 months.

Professor Donal O’Shea, the Health Service Executive (HSE) lead on obesity in Ireland, stated, “All the studies we had seen had pointed to weight going on when people stopped taking these drugs.” He likened the situation to the effects of discontinuing medication for chronic conditions such as blood pressure or cholesterol. The rapid weight regain could be attributed to significant weight loss experienced while on these medications.

In Ireland, the obesity landscape is concerning, with 37% of the population classified as overweight and an additional 23% as obese. While precise figures for users of weight-loss drugs are elusive, early estimates indicate that over 35,000 individuals used Ozempic for diabetes treatment in early 2025, leading to state costs surpassing €11 million in just one quarter.

The availability of weight-loss injections is complicated further by their high cost. Most patients access these jabs through private healthcare, with monthly expenses reaching up to €345. Additionally, there is a burgeoning online black market for these products, contributing to the challenge of regulating their use. The Health Products Regulatory Authority reported seizing over 11,000 unapproved doses in the 11 months leading up to November of last year.

An application for Mounjaro to be made available to public patients for obesity treatment was submitted late last year; however, Professor O’Shea noted that it has been deemed prohibitively expensive thus far. He expressed optimism that affordable generic versions could emerge within a few years, potentially enabling widespread access to long-term treatment.

Professor Susan Jebb, co-author of the study and advisor on obesity for the UK government, emphasized that obesity is a chronic relapsing condition. “These treatments need to be continued for life, in the same way as blood pressure medication,” she stated. Her perspective reinforces the need for a comprehensive approach that may include both injections and behavioral support to effectively address obesity.

The study, published in the British Medical Journal, warns that ceasing injection treatment not only reverses weight loss but also eliminates vital cardiometabolic benefits associated with these medications. Weight regained after stopping the injections occurs approximately four times faster than in individuals who achieve weight loss through diet and exercise alone.

Participants relying solely on diet and exercise typically lose around 5 kg on average over a year. They regain weight at a much slower rate, approximately 0.1 kg per month, with cardiometabolic improvements lasting up to five years after program completion.

Professor John Wilding, an honorary consultant physician at the University of Liverpool, echoed the findings, stating, “We don’t expect treatments for diabetes, high blood pressure, or high cholesterol to continue working once medication is withdrawn – and there’s no scientific reason obesity should be different.”

The implications of these findings could reshape the landscape of obesity treatment, highlighting the necessity for ongoing support for individuals seeking to manage their weight effectively. As the evidence mounts, the conversation surrounding the sustainability and long-term efficacy of weight-loss injections continues to evolve, calling for public health strategies that accommodate the chronic nature of obesity.