Mounjaro and Wegovy, two novel weight loss medications, have recently garnered significant attention. Whether through TV ads, celebrity endorsements, or shared success narratives on social platforms, chances are you've encountered one of these pharmaceuticals. If not, allow us to provide a brief introduction to each and highlight their distinctions. For a more comprehensive understanding, you can read this article.

Introduction to Mounjaro

Mounjaro (tirzepatide) is a medication developed by Eli Lilly and initially approved for medical use in the United states in May of 2022. It was approved by the U.S. Food and Drug Administration (FDA) as an adjunct to diet and exercise to improve blood sugar in adults with type 2 diabetes. Like other popular medications Ozempic, Wegovy, and Rybelsus, Mounjaro works by mimicking GLP-1 (glucagon-like peptide-1) hormone receptors, receptors in the gut responsible for feelings of fullness. Unlike these other medications, however, Mounjaro is a dual-acting medication, so it also activates GIP (glucose-dependent insulinotropic polypeptide) receptors. This dual-action is what truly sets Mounjaro apart from the competition, and is part of the reason it is so much more effective than traditional options. Mounjaro is not approved by the FDA for the treatment of weight loss specifically, but Zepbound is, which contains the same ingredient, tirzepatide. Before approval of Zepbound, Mounjaro was often prescribed off-label for weight loss anyway.

Intro to Wegovy

Wegovy (semaglutide) is a medication developed by Novo Nordisk and initially approved for medical use in June 2021. It belongs to the GLP-1 receptor agonist class of medications and mimics the hormone GLP-1. However, Wegovy received FDA approval in June 2021 for the treatment of obesity rather than diabetes and is administered via subcutaneous injection rather than orally. If you read this article, much of this information may sound familiar. That’s because it is! Though Ozempic and Wegovy are FDA approved for different conditions, there is virtually no other difference between them (other than recommended dosage). The relationship between Ozempic and Wegovy is the same as Mounjaro and Zepbound.

What Sets Them Apart?

Although Mounjaro and Wegovy are both GLP-1 receptor agonists, there are differences in chemical structure and method of action. As mentioned, Mounjaro contains the chemical tirzepatide, while Wegovy contains the chemical semaglutide. Without getting to into the weeds of the science, below is a brief comparison of the research studies. For our purposes, we will focus on the average amount of weight lost for each medication.

The Research

There are two relevant sets of research studies: the SURMOUNT trials and the STEP trials.  The SURMOUNT trials were funded by Eli Lilly for approval of Zepbound, while the STEP trials were funded by Eli Lilly for approval of Wegovy. There are currently two SURMOUNT trials with results, which can be viewed in more detail here. The SURMOUNT 1 trial, which only included non-diabetic individuals, found the average person lost 20.9% of their bodyweight on the highest dose over 72 weeks of treatment. The SURMOUNT 2 trial, which only included diabetic individuals, found the average person lost 14.7% of their body weight at the highest dose over 72 weeks of treatment. There are currently 8 published STEP trials, which ranged between 9.6% to 17.4% of average weight lost. The STEP trials can be viewed in more detail here. According to current research, the average individual on tirzepatide loses more weight than on semaglutide, though only by a few percentage points.

Which One Is Right for Me?

When deciding between Wegovy and Mounjaro, the answer usually comes down to cost and tolerability. Patients at MD Exam usually start taking semaglutide then switch to tirzepatide for more aggressive weight loss. Consistent with research, we have found that semaglutide generally has fewer and more mild side effects with more modest weight loss and lower cost. Before embarking on semaglutide or tirzepatide treatment for weight loss, it's crucial to consult a healthcare professional, such as the medical team at MD Exam. Through a comprehensive questionnaire and review of your medical history, we'll tailor a personalized weight loss plan. While both medications have demonstrated efficacy, individual results may vary slightly.

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