New research indicates that the heart health advantages of GLP-1 drugs like Mounjaro and Wegovy diminish quickly once treatment ends, prompting warnings from pharmacists about the risks of casual discontinuation amidst widespread usage.
A pharmacist has warned people taking weight-loss injections such as Mounjaro and Wegovy not to stop treatment casually, after new research suggested that the heart benefits of the drugs can fade within months of ending therapy. The caution comes as the medicines, part of the GLP-1 class, continue to be widely used for obesity and type 2 diabetes, with interest fuelled by their effects on weight, blood sugar and cardiovascular health.
According to BMJ Medicine, researchers at Washington University School of Medicine in St Louis followed 333,687 US military veterans with type 2 diabetes over three years and compared outcomes among those prescribed GLP-1 medicines with patients taking older diabetes tablets. The study found that people who stayed on semaglutide or tirzepatide had an 18% lower risk of heart attack, stroke or death than the comparison group, while those who stopped for two years lost almost all of that advantage and had a 22% higher risk.
The findings suggest the protective effect does not disappear instantly, but can erode surprisingly quickly after treatment ends. Even a six-month gap was linked with a measurable increase in risk once people restarted, and those who discontinued for long enough no longer appeared to have a meaningful cardiovascular advantage by the end of the study period. Senior author Dr Ziyad Al-Aly said many patients stop because of cost, side effects or shortages, and that the visible weight loss is not the only change taking place.
In the UK, the warning is likely to resonate with the large number of people now using these medicines. Research from University College London suggests about 1.6 million adults across the country have used weight-loss medication over the past year, with women making up a larger share of users than men and middle-aged adults forming the biggest group. The British Heart Foundation has also said Mounjaro can produce greater weight loss than Wegovy, and that both are used in NHS specialist weight-loss clinics alongside diet and exercise.
Palvinder Deol, superintendent pharmacist at Happy Pharmacy, said the research underlined that the drugs do more than reduce appetite and body weight. He said the medicines improve blood pressure, cholesterol and inflammation, all of which help protect the heart, and that those benefits can slip away long before the scale shows weight regain. Deol advised anyone considering stopping to speak to a pharmacist or prescriber first, especially if cost is the issue or if the medication is being used to manage blood sugar.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
