Mazdutide from Lilly: a new Mounjaro alternative?

Are you looking for an alternative to Wegovy and Mounjaro? A new injectable medication is on the horizon that may be of interest to you.

A drug called mazdutide was recently approved in China, and it's yielding positive results in clinical trials. Here's what you need to know about it.

What is mazdutide?

Mazdutide is a new medication that works similarly to Mounjaro (tirzepatide).

Like tirzepatide, it's a dual incretin agonist. In other words, it targets two hormones linked with appetite and metabolism.

How does mazdutide work?

Mazdutide acts as a GLP-1 and glucagon receptor dual agonist, meaning it stimulates both of these natural hormones at the same time.

This is promising. Mounjaro, the only dual incretin agonist currently on the market, yields an average weight loss of 21%. A recent mazdutide trial has seen an average weight loss of around 14%.

While that's less than Mounjaro's average, it's comparable to Wegovy (semaglutide). In a landmark clinical trial, Wegovy produced an average weight loss of around 15%.

How is it different from Mounjaro?

Mounjaro works by stimulating hormones called 'GLP-1' and 'GIP'.

Mazdutide also stimulates GLP-1. However, instead of GIP, it targets another hormone receptor called 'glucagon'. That makes it the first GLP-1 and glucagon dual agonist approved for weight loss.

What do we know from mazdutide studies?

In 2022, a phase 1 randomised trial tested mazdutide in 24 participants with obesity. Over 12 weeks, people taking the drug lost an average of 12% of their body weight, compared to just 1.8% in the placebo group.⁴

Then, in 2025, a phase 3 trial showed even more impressive results over a longer treatment period and at a lower dose. After taking the drug for 48 weeks, participants in this trial lost 14% of their body weight on average.²

This result puts mazdutide roughly on par with semaglutide, where a longer trial saw users lose 14.9% on average over 68 weeks.³

However, these were different trials under different conditions, which makes it difficult to draw any firm conclusions. 

That's where the most recent results come in. In a yet-to-be-published head-to-head trial comparing mazdutide and semaglutide under identical conditions, mazdutide came out on top. This trial saw mazdutide users lose an average of 10% over 32 weeks, compared to the semaglutide users' 6% average.⁵

It's worth noting, however, that the head-to-head trial was conducted on patients living with type 2 diabetes. The results for people without diabetes might vary.

When will mazdutide be available?

Mazdutide was approved as a weight loss treatment by China's medical regulators in June 2025.

However, it might not be available in countries like the UK and the US for some time. That's because the drug must go through tests and sign-offs in these countries before it can be approved for sale.

There's no guarantee mazdutide will be approved anytime soon – or at all. For now, Mounjaro injections remain one of the safest and most effective weight loss treatments on the UK market.

Are you considering using tirzepatide for weight loss? At SemaPen, we offer an expert-led Mounjaro programme created by UK obesity specialists. Why not take our digital consultation to find out if you're eligible today?

Sources

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

2. Ji, L. et al. (2025) "Once-Weekly Mazdutide in Chinese Adults with Obesity or Overweight" The New England Journal of Medicine, 392(22) https://doi.org/10.1056/NEJMoa2411528

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

4. Ji, L. et al. (2022) "Safety and efficacy of a GLP-1 and glucagon receptor dual agonist mazdutide (IBI362) 9 mg and 10 mg in Chinese adults with overweight or obesity: A randomised, placebo-controlled, multiple-ascending-dose phase 1b trial" eClinicalMedicine, 54:101691 https://doi.org/10.1016/j.eclinm.2022.101691

5. Turner, D. (2025) "Mazdutide shows superiority to semaglutide in a head-to-head trial" Drug Discovery World. Retrieved from https://www.ddw-online.com/mazdutide-shows-superiority-to-semaglutide-in-a-head-to-head-trial-38374-202510/

This article was reviewed and approved by Lujain Alhassan, Bariatric Nutritionist, on 27 November 2025.