July 9, 2024 – In a head-to-head comparison of the weight loss drugs Mounjaro and Ozempic, Mounjaro came out on top for helping people lose more weight. It was also found to be more effective at leading to significant weight loss compared to Ozempic.
While both drugs are intended for people who have type 2 diabetes, the new analysis included some people who did not have the condition and instead were taking the drugs in a practice known as off-label use.
The findings are based on an analysis of electronic health records. A records analysis is a different approach than a sometimes preferred but more tedious research method called a clinical trial, which is when people are recruited for a study under very specific criteria to help ensure a clear comparison. But these new findings from the records analysis are garnering serious attention because they were published in the American Medical Association’s prestigious journal JAMA Internal Medicine and are considered the first head-to-head comparison of the two drugs.
The active ingredient in Mounjaro is tirzepatide, and maker Eli Lilly also markets tirzepatide under the name Zepbound as a standalone weight loss drug. The active ingredient in Ozempic is semaglutide, and Novo Nordisk also makes a weight loss version called Wegovy. Both tirzepatide and semaglutide belong to the same class of drugs called GLP-1s.
The researchers looked at weight changes after the people had been receiving the medicines for 3, 6, and 12 months. They showed that:
- After 3 months, people taking tirzepatide lost on average 5.9% of their body weight, compared to 3.6% among people taking semaglutide.
- After 6 months, the tirzepatide group’s weight loss averaged 10.1%, compared to 5.8% for semaglutide.
- After 1 year, average body weight loss was 15.3% with tirzepatide, and 8.3% with semaglutide.
Those changes are equivalent to a 200-pound person losing just over 30 pounds after taking tirzepatide for 1 year, or losing just over 16 pounds after taking semaglutide for 1 year.
The results are in line with previous clinical trial results that separately evaluated weight loss among people taking the drugs, which have suggested that tirzepatide may lead to greater weight loss. Semaglutide was previously shown to aid in an average weight loss of about 15% of body weight after about 1 year and 4 months, and tirzepatide was linked to average weight loss of more than 20% after people took the drug for about 1 year and nearly 5 months.
For this latest study, researchers evaluated electronic health records for 41,222 adults whose average age was 52 and average starting weight was 243 pounds. The study was conducted by the private firm Truveta Inc., which is based in Washington state and specializes in electronic health record data analytics.
All of the people in the study were considered to be overweight or have obesity and received either semaglutide or tirzepatide between May 2022 and September 2023.
The researchers also analyzed reports in the people’s health records for gastrointestinal problems, which are common side effects with the medicines. The rates of GI problems for both drugs were similar.
