Is Mounjaro better than Wegovy (Ozempic)? A new study says 'Yes'

A new clinical trial directly compares Wegovy and Mounjaro. Learn what this means for doctors and patients.



This is despite Wegovy having a head start. Wegovy was approved as a weight loss treatment in the UK in September 2023, while Mounjaro followed in January 2024.

Are more people searching for Mounjaro because Mounjaro is better than Wegovy?

Separate clinical trials have suggested that Mounjaro outperforms Wegovy in terms of total weight loss. Until recently, however, we've had no data that directly compare the new medications.

But now, we can say with certainty that Mounjaro is more effective than Wegovy. And it's all thanks to a new study announced yesterday by Mounjaro's manufacturer, Eli Lilly.

What does the study show?

The study is the latest in a series of clinical trials called 'SURMOUNT'. These trials are sponsored by Eli Lilly and aim to investigate Mounjaro's potential as a weight loss treatment.

Known as 'SURMOUNT-5', this new trial saw participants randomly selected to begin treatment with Wegovy or Zepbound – the US brand name for Mounjaro.

After 72 weeks of treatment:

• Participants taking Zepbound lost 20.2% of their starting weight, on average.
• Those taking Wegovy lost an average of 13.7%.

As the study says, this means "Zepbound (tirzepatide) provided a 47% greater relative weight loss compared to Wegovy (semaglutide).

What's special about the new study?

A 47% increase in weight loss is nothing to sniff at. But these results were hardly unexpected.

Separate clinical trials have already suggested that Mounjaro outperforms Wegovy for weight loss.

• In 2022's SURMOUNT-1 trial, participants who took the highest dose of Mounjaro lost an average of 21% of their starting weight.¹
• In the STEP 1 trial from 2021, participants who took the highest dose of Wegovy lost an average of 14.9% of their starting weight.²

However, these are separate trials with separate parameters. Based on these results alone, we can't say 'Mounjaro is definitely better than Wegovy' because the data aren't directly comparable.

That's why the SURMOUNT-5 trial is so significant. It's the first study that pits the two medications against one another under identical conditions.

This means there's now very little room for doubt. Previously, small differences between the Mounjaro and Wegovy studies made direct comparisons difficult. But now we finally have data that demonstrate a clear advantage for Mounjaro.

What does this mean for SemaPen?

While Mounjaro is now cemented as the more effective medication, we know it's not for everyone.

Mounjaro and Wegovy are part of the same family of drugs but have several important differences. They work in different ways, have different dosing schedules and can produce different side effects.

That's why we'll continue to offer Mounjaro and Wegovy treatment programmes. This way, our subscribers can choose the medication that best fits their needs and circumstances.

Want to learn more about injectable weight loss medications? Our expert guides are a good place to start.

* Ozempic and Wegovy are drugs with the same active ingredient (semaglutide). However, Wegovy is approved as a weight loss treatment in the UK, while Ozempic is only approved to treat type 2 diabetes.

Sources

1. Jastreboff, A.M. et al. (2022) "Tirzepatide Once Weekly for the Treatment of Obesity" New England Journal of Medicine, 387(3) https://doi.org/10.1056/NEJMoa2206038

2. Wilding, J.P.H. et al. (2021) "Once-weekly semaglutide in adults with overweight or obesity" New England Journal of Medicine, 384(11) https://doi.org/10.1056/NEJMoa2032183