- Tirzepatide leads to greater weight loss but also more lean body mass loss than semaglutide
- Study analyzed data from 8,000 patients using tirzepatide or semaglutide for weight loss
- Muscle loss may reduce physical performance and increase risk of injury during weight loss
Weight loss drugs have transformed the way obesity is treated, with medications like Tirzepatide and Semaglutide leading the charge. Sold under popular brand names such as Zepbound, Mounjaro, Wegovy, and Ozempic, over the period of time these drugs have gained massive popularity for their ability to deliver significant weight loss. But a new study suggests there may be a trade-off. While tirzepatide may lead to greater weight loss, it could also result in higher loss of muscle and other components of lean body mass compared to semaglutide. The analysis, conducted by Massachusetts-based firm nference, examined data from around 8,000 patients, including approximately 1,800 using tirzepatide and 6,200 using semaglutide
What The Study Found
Researchers found that tirzepatide was consistently associated with greater lean body mass loss. On average: Patients on tirzepatide lost about 1.1 percent more lean mass after three months. After 12 months, the difference increased to around 2 percent. This finding is significant because lean body mass includes muscle, connective tissue, and other essential components that support strength, metabolism, and overall physical function.
Why Muscle Loss Matters
Weight loss is often seen as a positive outcome, but not all weight loss is equal. Losing fat is beneficial, but losing muscle can have downsides. Muscles play a key role in maintaining metabolism, strength, and mobility. Excessive loss of lean body mass may lead to reduced physical performance, fatigue, and even increased risk of injury. Experts warn that focusing only on the number on the scale can be misleading.
How These Drugs Work
Both tirzepatide and semaglutide belong to a class of drugs that mimic hormones involved in appetite regulation. Semaglutide works by mimicking GLP-1, a hormone that helps control hunger and blood sugar levels. Tirzepatide, on the other hand, mimics both GLP-1 and another hormone called GIP. This dual action is believed to enhance weight loss by slowing digestion and increasing the feeling of fullness. However, researchers say it is still unclear why this may also lead to greater muscle loss.
Who Is At Higher Risk?
The study also highlighted certain factors that may increase the risk of losing lean body mass:
- Higher doses and longer duration of treatment
- Pre-existing musculoskeletal conditions
- Lower tolerance for exercise during treatment
Interestingly, about 10 percent of tirzepatide users who lost more than 20 percent of their body weight also lost over 5 percent of their lean mass. In comparison, this was seen in fewer than 7 percent of semaglutide users achieving similar weight loss.
The Role Of Exercise
One of the most important takeaways from the study is the role of physical activity. Researchers found that reduced exercise tolerance during treatment was linked to greater muscle loss in both groups, especially among those taking tirzepatide. This creates what experts describe as a "vicious cycle". As muscle mass declines, physical activity becomes more difficult, which in turn leads to further muscle loss. Maintaining strength training and regular exercise during treatment may help counter this effect.
What Drugmakers Say
The clinical trials did not show significant differences in muscle mass compared to placebo, and that physical function was preserved. Meanwhile, Eli Lilly, the maker of tirzepatide, has not yet responded to the findings. It is important to note that the study results have been published ahead of peer review, meaning further validation is needed. Drugs like tirzepatide and semaglutide are powerful tools in the fight against obesity, offering significant weight loss and additional health benefits such as improved heart health. However, this study highlights an important consideration: more weight loss does not always mean better outcomes, especially if it comes at the cost of muscle health.
Also read: Tirzepatide And Semaglutide: Experts Explain New Diabetes, Obesity Drug Options
For those considering these medications, the key lies in a balanced approach, combining medical treatment with proper nutrition and regular exercise. Because when it comes to sustainable weight loss, preserving strength may be just as important as shedding kilos.
Disclaimer: This content, including advice, provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.
