Real World Study Compares Weight Loss with Semaglutide vs Tirzepatide

While tirzepatide (Mounjaro) was significantly more effective than semaglutide (Ozempic), patients on both medications experienced substantial weight loss and we observed no difference in the risk of GI adverse events. Interview with:
Tricia Rodriguez, PhD, MPH

Nick Stucky, MD, PhD
Three of the authors of the JAMA Internal Medicine study  What is the background for this study? What are the main findings?

Response: With over 70% of US adults having overweight or obesity, GLP-1s have the potential to be used by a huge number of people. We’ve seen dramatic increases in use by patients with and without type 2 diabetes in the past year, yet little real-world data exist to compare the effectiveness of two of the most common medications, semaglutide (Ozempic) and tirzepatide (Mounjaro). Head-to-head trials for patients with overweight or obesity are still months away, and even then, it remains unclear how weight loss observed in these randomized controlled trials will generalize to real-world populations. There has been evidence that these medications are effective for weight loss, but it hadn’t been clear just how effective they are, particularly in relation to each other.

While clinical trials don’t always generalize to the real-world, our findings were broadly consistent with placebo-controlled clinical trials, finding that the majority of patients on both medications experience clinically meaningful weight loss within a year on treatment. However, patients on tirzepatide (Mounjaro) were over 2 times more likely to experience 10% weight loss and 3 times more likely to experience 15% weight loss within a year, compared to patients on semaglutide (Ozempic).  Our study also found that, in general, patients without type 2 diabetes experienced greater weight loss than patients with type 2 diabetes, but tirzepatide (Mounjaro) was more effective than semaglutide (Ozempic) in both groups.

The study also found a high rate of discontinuation – 55.9% of patients on tirzepatide (Mounjaro), and 52.5% of patients on semaglutide (Ozempic) within 12 months.

Gastrointestinal side effects of these medications have been widely reported as well, but we didn’t find a difference in the rates of moderate to severe gastrointestinal adverse events between the two medications.

— Tricia Rodriguez, PhD, MPH principal applied scientist, Truveta Research, and lead author on the paper

Last Updated on July 10, 2024 by weightcontrol