One slimming injection is more effective than the other
People can combat excess weight with injection medications like Wegovy and Mounjaro. A study now shows that one of the two active ingredients is significantly more effective. However, it is clear what the problem with the injections is - and here, the two preparations do not differ.
A comparative study confirms that a greater weight loss can be achieved with the active ingredient Tirzepatide than with Semaglutide. Tirzepatide is sold in Germany as "Mounjaro," and Semaglutide is in the "Wegovy" injection medications. The side effect risk of both substances is comparable, reports a research team in the journal "JAMA Internal Medicine." However, statements on long-term effects and the achievement of important goals such as a reduced risk for heart attacks could not be derived from the analysis.
Both active ingredients have been used for the treatment of Type-2 diabetes for a longer time and since 2023 also for overweight or obese people without diabetes - where patients are supposed to adjust their diet and move more for weight loss. Tirzepatide is sold in Germany by the pharmaceutical company Eli Lilly under the name "Mounjaro." Novo Nordisk markets Semaglutid as "Wegovy."
The researchers around Nicholas Stucky from the US company Truveta in Bellevue, which specializes in analyzing electronic health data, used data from about 18,000 adults with obesity or overweight in the USA who were treated with Wegovy or Mounjaro injections. Their average age was 52 years, and the average weight at the start of treatment was 110 kilograms.
More than Half Discontinue Treatment
Data was recorded on whether a weight loss of at least 5%, 10%, or 15% was achieved and how the weight developed after 3, 6, and 12 months of treatment. Patients who received the Mounjaro active ingredient achieved this more frequently and with greater average weight loss.
The results confirm hints from earlier studies, say the researchers. Some details of the data: About 82% of men and women treated with Mounjaro injections achieved a weight loss of 5% or more, while about 67% did so with the Wegovy active ingredient. A reduction of 15% or more was achieved by about 42% (Tirzepatide) and 18% (Semaglutide). The rate of gastrointestinal side effects such as nausea, diarrhea, and constipation as side effects was similar in both groups.
One insight from the study pushes the question of effectiveness into the background: More than half of the included women and men discontinued treatment. The difference was small between Tirzepatid and Semaglutide. The reason for discontinuation was not recorded, explain the researchers. Possible reasons could be unwanted side effects, high costs of self-paying therapy, or supply issues with the preparations.
Long-term Effects? Unclear
The high dropout rate is concerning, as several studies have shown that after discontinuation, there is a significant rebound effect: The weight increases significantly after discontinuation. The active ingredients must therefore be used for a sustained effect - but the long-term effects are still unclear.
Tirzepatide and Semaglutide belong to the so-called GLP-1 receptor agonists. In the public, they are now known as drugs for weight loss - not least because US celebrities use such injections. The substances mimic the effect of the body's own GLP-1 hormone. In the brain, they set the signal to feel full. Hunger feelings are reduced, hunger attacks are less frequent and less strong, and the preference for particularly energy-dense foodstuffs fades away.
Since July 17 of the previous year, doctors and physicians in Germany have been able to prescribe "Wegovy" with the active ingredient Semaglutide for weight loss. Patients inject themselves the medication with a type of pen once a week into their skin. "Wegovy" is intended for adults with a Body-Mass-Index (BMI) of 30 or more, i.e. people with obesity. Included are also overweight persons (BMI 27 or higher) with weight-related comorbidities. "Mounjaro" has been approved for this purpose in the USA and the EU since the end of the previous year.
The study findings suggest that Tirzepatide, the active ingredient in Mounjaro, is more effective than Semaglutide in Wegovy for achieving significant weight loss in overweight or obese individuals, regardless of diabetes status. However, the long-term effects and their impact on health goals like reduced heart attack risk remain uncertain. Additionally, the high discontinuation rate of these medications, affecting both Tirzepatide and Semaglutide users, is a concern due to potential rebound weight gain after treatment cessation.
