Big study indicates that people taking the diabetic medication Mounjaro shed more weight than those on Ozempic.

A recent study involving real-world patients has shown that Mounjaro (tirzepatide), an injectable medication, leads to more significant weight loss in overweight and obese adults compared to its competitor, Ozempic (semaglutide). Both medications, originally prescribed for type 2 diabetes, mimic the effects of the gut hormone GLP-1, which not only enhances insulin production and slows down food movement through the stomach but also helps control appetite by signaling the brain. Tirzepatide has an added mechanism, stimulating another gut hormone, GIP, potentially boosting its effectiveness.

These drugs have recently gained attention for their potential in aiding substantial weight loss. The study, which is yet to be peer-reviewed or published in a professional journal, aligns with results from clinical trials. The effectiveness of tirzepatide, observed by many doctors in their diabetes patients, raised the possibility of its superior potency compared to semaglutide. However, comparative studies between these drugs, especially among non-diabetic individuals, have been limited. An ongoing investigation is comparing them, but results are expected in over a year.

Dr. Patricia Rodriguez, the lead author of the study and a senior applied scientist at Truveta Research, highlighted the significant potential of these medications given the high prevalence of overweight and obesity in the American adult population. She also pointed out the current gap in information regarding their use.

This study was independently initiated by Truveta, a data analytics firm owned by 30 US healthcare systems, rather than being sponsored by the drug manufacturers. Truveta utilizes anonymized patient records from these healthcare systems to conduct research and answer pertinent medical questions.

Comparing drugs used to lose weight

Due to their effectiveness in weight loss, the US Food and Drug Administration has authorized higher doses of tirzepatide and semaglutide for weight management, marketed as Zepbound and Wegovy, respectively. The study in question, however, focused on the lower doses approved for treating type 2 diabetes, which may impact the breadth of its findings. This investigation covered patient records from May 2022 to September 2023.

Dr. Rodriguez and her team analyzed thousands of records, identifying overweight and obese adults using Mounjaro or Ozempic. The study included over 18,000 individuals, with slightly more than half diagnosed with type 2 diabetes. The remaining 48%, with no diabetes history recorded, were presumed to be using the drugs off-label for weight loss at their doctor’s recommendation.

One notable observation was that continued use of these medications correlated with greater weight loss. However, about half of the participants discontinued the drugs during the study. The reasons for discontinuation were unclear, but both medications were experiencing shortages, which may have affected availability.

Nausea and vomiting were the most common side effects, affecting approximately one in five users. Gallstones were reported in about one in six participants. The study found no significant differences in side effect rates between the two medications.

Weight loss was more pronounced in non-diabetic participants, but among those with diabetes, Mounjaro users lost a larger percentage of their initial weight compared to Ozempic users. At three, six, and twelve months, Mounjaro users consistently showed higher average weight loss percentages than Ozempic users. After adjusting for potential biases, the differences in weight loss between the two medications were less pronounced.

Whichever works is the best.

Dr. Mopelola Adeyemo, who specializes in treating diabetes and obesity at the University of California, Los Angeles, noted that the study’s findings are consistent with clinical trials and thus not entirely unexpected. Adeyemo emphasized that the most effective weight loss medication varies from person to person. She mentioned that some of her patients are unable to tolerate certain GLP-1 medications like Ozempic or Mounjaro, but can manage others.

Adeyemo believes that both medications have significant roles to play. “Both have been proven to aid in weight loss and offer additional benefits for diabetes management and cardiovascular health,” she said.

Novo Nordisk, the maker of Ozempic and Wegovy, criticized the study for not being a fair comparison. The company pointed out that the doses of semaglutide used in the study were not intended for chronic weight management and lacked direct comparison trials with Wegovy and tirzepatide. They also highlighted that semaglutide is administered at a higher dose for weight loss purposes.

Rodriguez agrees with the company’s stance, expecting higher weight loss with obesity-labeled medications due to their increased dosages.

Eli Lilly, the manufacturer of Mounjaro and Zepbound, does not endorse the off-label use of its drugs. The company advocates for patience as it continues to gather more data on these medications.