Research: Kilos come back after you stop using the slimming drug

There is some hope for medicines in the fight against severe obesity, but research shows increasing evidence for a yo-yo effect after quitting.

The active ingredient tirzepatide showed significant weight gain in patients when they were given a dummy drug only after 36 weeks of taking the drug. A research team reports this in the magazine “Jama”. However, in the second group of subjects who continued to take the medication, the pounds continued to fall. The results come as no surprise to experts.

According to the study, tirzepatide has so far been approved for the treatment of obesity in the US, but not yet in the EU. There it can currently only be used under the name “Mounjaro” in certain cases of type 2 diabetes. Tirzepatide is considered even more effective than the active substance semaglutide (“Wegovy”), which until now is often referred to when it comes to injections for weight loss. As with semaglutide preparations, study participants must also follow a diet and be sufficiently physically active.

The study involved 670 patients from different countries who were obese or overweight at baseline. After 36 weeks, they had reduced their weight by an average of about 21 percent, the team reports. Some of the test subjects also received the active substance afterwards and lost another 5.5 percent weight in week 88 of the study. After the first phase, the researchers only gave a second group a placebo: at the end of the study, this group had increased significantly again. Yet the subjects recorded a weight loss of about ten percent over the entire study period.

From the study authors’ point of view, the results emphasize that therapy must be continued if you want to prevent weight gain again. At least five studies of different classes of drugs – including the current one – have shown that there is a clear yo-yo effect after discontinuation. This also included semaglutide. Further research would be needed to understand the potential long-term benefits and risks of short-term therapies.

The results are “anything but surprising,” says Stephan Martin, chief physician for diabetology and director of the West German Diabetes and Health Center in Düsseldorf, pointing to almost identical study results for semaglutide. It should also be noted that the research participants are specially selected, motivated and also particularly trained in terms of lifestyle.

Due to less care in daily practice, patients can even gain weight more quickly after stopping therapy. “The research clearly shows that the ‘miracle syringes’ must be used for life,” says Martin.

The research also shows that side effects are relatively common and mainly affect the gastrointestinal tract: such as nausea, diarrhea and constipation. This is comparable to semaglutide preparations. Severity is described in the study as mostly mild to moderate, and side effects became less common over time. However, some people stopped participating in the study due to side effects. (sda/dpa)