Mazdutide is one of several next-generation weight-loss peptides that pair GLP-1 activity with a second hormone pathway. It's notable both for its distinct mechanism and for being one of the few drugs in this class already approved for use, just not in the United States.

What It Is

Mazdutide (also known by its development codes IBI362 and LY3305677) is a dual agonist that activates both the GLP-1 receptor and the glucagon receptor. It's structurally based on oxyntomodulin, a naturally occurring gut hormone that activates both of those same receptors. It was jointly developed by Chinese biotech Innovent Biologics and Eli Lilly.

How It's Different From Tirzepatide

Mazdutide's mechanism is easy to confuse with tirzepatide (Zepbound/Mounjaro), but the two work differently. Tirzepatide pairs GLP-1 receptor activity with GIP receptor activity. Mazdutide instead pairs GLP-1 with glucagon receptor activity. Activating the glucagon receptor is associated with increased energy expenditure and fat oxidation, on top of the appetite suppression and glucose-regulating effects that come from the GLP-1 side. This dual-agonist approach targeting GLP-1 plus glucagon is the same general mechanism behind survodutide, a different peptide from Boehringer Ingelheim and Zealand Pharma, covered in a separate guide on this site, though the two molecules are distinct compounds from unrelated companies.

Regulatory Status

China's National Medical Products Administration (NMPA) approved mazdutide for chronic weight management in adults with obesity or overweight in June 2025. Innovent later announced a separate NMPA approval for glycemic control in adults with type 2 diabetes. Mazdutide is not approved by the FDA and remains investigational in the United States and most markets outside China.

What the Trial Data Shows

Mazdutide's Chinese Phase 3 program, published in trials known as GLORY-1 and GLORY-2, has reported weight loss of up to roughly 20% at the highest studied dose (9 mg) in Chinese adults with obesity, with the GLORY-1 results published in the New England Journal of Medicine. A separate head-to-head Phase 3 trial (DREAMS-3) reported that mazdutide outperformed semaglutide on measures of both glycemic control and weight loss in the trial population studied. These are real, published results, but they come from trials conducted specifically in Chinese populations; how the drug performs in other populations, including under FDA-standard trial design, hasn't yet been established through a comparable US regulatory filing.

Availability Outside China

Because mazdutide isn't FDA-approved, any product sold in the US under that name is not a legitimate, regulated pharmaceutical, regardless of how it's marketed. Peptide vendors selling "mazdutide" as a research chemical are operating entirely outside the approval and quality-control process that governs the actual Innovent/Lilly drug in China.

Safety Considerations

As a GLP-1/glucagon dual agonist, mazdutide's studied side effect profile includes gastrointestinal effects common across this drug class, such as nausea and diarrhea. Because there is no FDA-approved labeling for mazdutide, there is no US-standard prescribing information or safety monitoring framework for it, and any product sold outside a regulated pharmacy supply chain carries the additional, separate risk of unverified purity and dosing.

The Bottom Line

Mazdutide represents genuine, published clinical progress in a legitimate national regulatory system, and it's a useful example of how a peptide drug's approval status can differ sharply between countries. It is not an FDA-approved option in the US, and anyone interested in GLP-1/glucagon dual-agonist therapy should discuss FDA-approved or actively enrolling US clinical trial options with a physician rather than seeking mazdutide through unregulated channels.