A major new global data review highlights a significant challenge in long-term obesity management, many individuals who achieve weight loss using popular anti-obesity medications, such as Wegovy (semaglutide) and Mounjaro (tirzepatide), regain a substantial amount of that weight within about two years of stopping treatment. Experts emphasise that this pattern underscores the necessity of treating obesity as a chronic, relapsing condition requiring sustained, comprehensive support, rather than a short-term pharmacological fix.
The review, which analysed 37 clinical studies involving over 9,300 participants, found that people who stopped taking weight-loss drugs regained weight at an average rate of 0.4 kg per month. A full return to baseline weight was projected to occur approximately 1.7 years after discontinuation. Importantly, metabolic improvements also reversed, with key heart health markers like blood pressure and cholesterol typically reverting to pre-treatment levels within about 1.4 years, reinforcing the broader health implications of halting treatment. Patients on GLP-1 receptor agonists (like semaglutide and tirzepatide) experienced faster rebound weight gain than those who lost weight through diet and exercise alone, with one analysis showing weight regain after stopping medication can be nearly four times faster than in traditional dieters.
The effectiveness of GLP-1 drugs is linked to their mechanism of suppressing appetite and modifying hunger signals. Once the medication is stopped, these appetite and metabolic drivers tend to revert to their baseline state, making it extremely difficult for many users to sustain weight loss without continued lifestyle and behavioural support.
These findings have significant implications for treatment protocols and policy. Experts argue that effective weight management must combine medication with long-term lifestyle interventions, including dietary support, physical activity, behavioural therapy, and environmental changes, to maintain benefits beyond the drug treatment period. Current guidelines, such as those from NICE in the UK, often recommend a maximum two-year course of GLP-1 therapy. However, the new evidence suggests clinicians and patients must plan for post-medication maintenance and may need to consider longer-term or even indefinite medication for certain individuals, similar to the management of chronic conditions like hypertension. In reality, factors such as cost, accessibility issues, side effects, and diminishing perceived benefit lead many patients to stop anti-obesity medications prematurely, meaning only a minority receive treatment long enough to reach long-term goals. For health systems, the widespread use of these drugs requires considering the long-term sustainability of treatment, with cost-benefit analyses now needing to account for the high probability of weight regain and subsequent healthcare costs if treatments are halted without robust support structures.
While anti-obesity drugs like Wegovy and Mounjaro deliver significant short-term weight loss and metabolic improvements, evidence confirms that weight regain within two years of cessation is a common outcome. This strongly supports the view that obesity is a chronic condition demanding comprehensive, sustained management that extends far beyond the duration of drug therapy alone.
