People who stop taking the weight-loss jab Mounjaro are likely to regain weight and may see improvements in blood pressure and cholesterol levels reversed, new research suggests.
Mounjaro, which contains the active ingredient tirzepatide, has become a popular treatment for obesity, with studies showing patients can lose an average of 20% of their body weight after 72 weeks. However, previous research has indicated that stopping the medication often leads to significant weight regain.
In the latest analysis, based on data from the Surmount-4 clinical trial, researchers examined outcomes for 308 participants who had lost at least 10% of their body weight during an initial 36-week course of tirzepatide. After being randomly assigned to continue the drug or receive a placebo for a further 52 weeks, those who stopped treatment tended to put weight back on. One year later, 82% had regained at least a quarter of the weight they had originally lost.
The team, writing in JAMA Internal Medicine, found that greater weight regain was associated with a corresponding reversal of improvements in waist circumference, "bad" cholesterol, blood pressure and blood glucose levels. Participants who regained 75% or more of the lost weight saw these measures return to their baseline values, although those who kept off at least half the weight retained some benefits.
Professor Naveed Sattar of the University of Glasgow said the findings were unsurprising. "When weight lost through therapeutic interventions is regained, these cardiometabolic risk factors typically rise in proportion to the speed and extent of weight regain," he said. Jane Ogden, emeritus professor at the University of Surrey, said weight-loss jabs do not necessarily encourage healthier eating and exercise habits. "Once stopping taking the medication, people show weight regain as they return to their previous behaviours," she added.
