A large study found that users of the diabetes drug Mounjaro lost more weight than users of Ozempic


Overweight and obese adults who took the injected drug Mounjaro lost more weight and were more likely to reach certain weight-loss goals than people who took a similar competing product, Ozempic, according to a new study of people who took the drugs in the real world.

Both Ozempic, or semaglutide, and Mounjaro, or tirzepatide, mimic the effects of the gut hormone GLP-1, which stimulates the body’s production of insulin and slows the passage of food through the stomach. GLP-1 also signals the brain to help control appetite. Tirzepatide also stimulates a second gut hormone called GIP, which may help increase its effects.

The drugs are prescribed to treat type 2 diabetes, but are enjoying renewed popularity because they can also help people lose significant amounts of weight.

The new study is a preprint that has not been peer-reviewed or published in a scientific journal. The results are consistent with observations from clinical trials, and many doctors had suspected that tirzepatide might be more effective after seeing the results in their diabetes patients. However, to date there have not been many studies directly comparing the drugs, particularly in people who do not have diabetes. Such an investigation is underway, but results are not expected for another year.

“Over 70% of American adults If you are overweight or obese, there is huge potential for using these medications [there’s] “Really a lack of information,” said lead study author Dr. Patricia Rodriguez, a senior applied scientist at Truveta Research.

The study was not sponsored by any of the drug manufacturers. Instead, it was initiated by Truveta, a data analytics company owned and operated by 30 U.S. health systems. Truveta brings together anonymous patient records from these hospitals and uses them to answer research questions.

Because of their weight loss benefits, the U.S. Food and Drug Administration has approved higher doses of tirzepatide and semaglutide for weight loss under the names Zepbound and Wegovy, respectively. The new study only looked at doses approved for treating type 2 diabetes, which could limit its conclusions. The recordings covered the period between May 2022 and September 2023.

Rodriguez and her team combed through thousands of patient records to find overweight and obese adults on Mounjaro or Ozempic.

Of the more than 18,000 people included in the study, just over half – 52% – had type 2 diabetes. The other 48% had no documented history of diabetes in their medical records, so researchers concluded that this group of more than 9,000 people were likely taking the drugs off-label at their doctor’s discretion, solely for weight loss.

People lost more weight the longer they took the medication, but many stopped taking the medication. About half of the people included in the study stopped taking it during the study period.

The authors note that it is difficult to say why people stopped filling their prescriptions. Both drugs examined in the study were in shortage, which may have made them difficult to find.

The most common side effects listed in medical records were nausea and vomiting, which occurred in about one in five people taking the medication. Gallstones have been reported in about one in six people. The study authors note that side effects were very similar between the drugs and they found no significant differences in the rates of adverse events

People lost more weight on the medication if they didn’t have diabetes, but even if they did, those who took Mounjaro lost a greater percentage of their starting weight than those who took Ozempic.

After three months, the average weight loss for Mounjaro users was about 6%, compared to almost 4% for those taking Ozempic. After six months, the average weight loss for Mounjaro was 10%, compared to 6% for Ozempic. After 12 months, people on Mounjaro had lost an average of 15% of their body weight, compared to about 8% on Ozempic. After the researchers adjusted their data for potential sources of bias, these differences narrowed.

The results of the study do not differ significantly from the results of clinical trials and are therefore not particularly surprising, says Dr. Mopelola Adeyemo, who treats people with diabetes and obesity at the University of California, Los Angeles.

Adeyemo says that ultimately, the best weight loss drug for a person will be the one that works for them. She has patients who cannot tolerate one form of a GLP-1 drug, such as Ozempic or Mounjaro, but can take another.

“I think there will definitely be a role for both because both have been shown to help not only with weight loss but also with diabetes and other cardiovascular benefits,” Adeyemo said.

Novo Nordisk, the company that makes Ozempic for diabetes and Wegovy for weight loss, said the study was not a fair comparison.

“The doses of semaglutide evaluated in this analysis were not studied for chronic weight control, and there are no comparative studies evaluating Wegovy and tirzepatide,” a spokesperson said in a statement.

The company notes that semaglutide is taken at a higher dose for weight loss.

“We totally agree,” Rodriguez said. “That’s what we expect when it comes to obesity labeling With medication, we would expect people to lose more weight because the dosages are significantly higher.”

Eli Lilly, the company that makes Mounjaro and Zepbound, said it does not tolerate off-label use of its drugs. It requires patience while getting more information.

“Our SURMOUNT-5 study, which is a head-to-head study comparing tirzepatide (Zepbound) and semaglutide (Wegovy) for the treatment of obesity or overweight with weight-related comorbidities, is expected to be completed in 2025,” said a spokesman said in an email.