In a groundbreaking study, the first head-to-head trial comparing two leading weight-loss drugs, Mounjaro and Wegovy, has found that Mounjaro is significantly more effective for weight reduction. The trial, which evaluated the efficacy of both medications over a span of 72 weeks, revealed that participants using Mounjaro experienced an impressive 20% weight loss, in contrast to the 14% weight loss reported by participants taking Wegovy.
Both Mounjaro and Wegovy function by influencing the brain's appetite regulation, leading to reduced food intake and increased fat burning. However, the two drugs operate through different mechanisms. Wegovy, chemically known as semaglutide, mimics a hormone that the body naturally releases after meals, activating one specific appetite-regulating pathway in the brain. In contrast, Mounjaro, also known as tirzepatide, activates two different pathways, which may account for its superior results in weight loss.
The trial, funded by Eli Lilly, the manufacturer of Mounjaro, included 750 participants with obesity, each averaging a weight of 113 kg (nearly 18 stone). Participants were instructed to take the highest tolerable dose of either Mounjaro or Wegovy. The findings were presented at the European Congress on Obesity in Malaga and published in the New England Journal of Medicine. Key results included:
32% of individuals on Mounjaro lost a quarter of their body weight, compared to 16% on Wegovy. Participants on Mounjaro lost an average of 18 cm from their waistlines, while those on Wegovy lost 13 cm. Individuals taking Mounjaro showed better improvements in blood pressure, blood sugar, and cholesterol levels. Side effects were reported to be similar for both medications.Interestingly, findings indicated that women tended to achieve more significant weight loss compared to men throughout the trial.
Dr. Louis Aronne, who led the study at the Comprehensive Weight Control Center at Weill Cornell Medicine in New York, stated, “The majority of people with obesity will do just fine with semaglutide (Wegovy), but those at the higher end of the scale may ultimately benefit more from tirzepatide (Mounjaro).”
In the UK, both Mounjaro and Wegovy are accessible through specialist weight-management services and can also be purchased privately. Professor Naveed Sattar from the University of Glasgow noted that while both medications are effective, there is a clear trend where private sales of tirzepatide are currently outpacing those of semaglutide. He emphasized that this new study could further accelerate this trend.
It is important to note that Wegovy is also licensed for additional medical uses, such as preventing heart attacks, whereas equivalent trials for Mounjaro are still pending completion. A substantial amount of research is ongoing in the field of weight-loss drugs, including testing higher doses of existing medications and exploring new delivery methods, such as oral pills. Additionally, new medications that target different biological pathways are under investigation.
Professor Sattar expressed optimism regarding the future of obesity prevention, suggesting that the current wave of research may soon lead to effective preventive measures. However, he also stressed the importance of societal changes to improve overall health and prevent obesity from becoming a prevalent issue.
