Mazdutide is a once-weekly injectable peptide that activates two receptors at once: the GLP-1 receptor and the glucagon receptor. It started life at Eli Lilly as LY3305677 and is being developed in China by Innovent Biologics under license, where it carries the code IBI362. In June 2025 it became the world's first dual glucagon/GLP-1 receptor agonist approved for weight management, according to Innovent's announcement of the NMPA approval.
What it is
Chemically, mazdutide is a synthetic analogue of oxyntomodulin, a gut hormone the body releases after eating that naturally hits both the GLP-1 and glucagon receptors. The molecule has been modified with a fatty-acid chain to slow its clearance, which is what allows once-weekly dosing. The NEJM report on its pivotal trial describes it plainly as "a mammalian oxyntomodulin analogue."
The dual mechanism is the point of difference. GLP-1 receptor activation drives the appetite-suppression and blood-sugar effects familiar from drugs like semaglutide. Adding glucagon receptor activity is intended to raise energy expenditure and improve liver fat metabolism on top of that. Innovent describes the combination as targeting weight, glucose, and visceral fat together.
What the research shows
The evidence base here is substantial, not speculative. Early phase 1b work in Chinese adults established the dose range and tolerability. A phase 1b trial in adults with overweight or obesity00421-7/fulltext), published in eClinicalMedicine in 2022, tested 9 mg and 10 mg doses and reported the drug was well tolerated with meaningful weight reduction over 12 weeks.
The pivotal data come from GLORY-1, a phase 3 randomized, placebo-controlled trial of 610 Chinese adults with obesity (or overweight plus a related comorbidity). Participants got mazdutide 4 mg, 6 mg, or placebo by once-weekly injection for 48 weeks. Results were published in the New England Journal of Medicine in May 2025:
| Group | Mean weight change at week 48 | Achieved at least 15% loss |
|---|---|---|
| Mazdutide 4 mg | about -12.0% | 37.0% |
| Mazdutide 6 mg | about -14.8% | 50.6% |
| Placebo | about -0.5% | 2.1% |
Waist circumference fell roughly 9.5 cm (4 mg) and 11.0 cm (6 mg) versus 1.5 cm on placebo. The trial reported no signal of increased cardiovascular risk. Innovent has also reported higher-dose data: a 9 mg arm in the GLORY-2 program reaching around 20% weight loss, and a head-to-head trial (DREAMS-3) comparing it against semaglutide in type 2 diabetes.
Regulatory status
Mazdutide's approvals are, so far, specific to China. The National Medical Products Administration (NMPA) approved it on June 27, 2025 for chronic weight management in adults with a BMI of 28 or above, or 24 or above with a weight-related condition. A separate NMPA approval followed on September 19, 2025 for glycemic control in adults with type 2 diabetes. It is not approved by the FDA or EMA. The lower dose strengths (4 mg and 6 mg) underpin the weight-management approval.
Because it is a peptide drug that acts on metabolism, mazdutide is also relevant to anti-doping. Athletes should check the current WADA Prohibited List directly rather than rely on a general summary, since hormone and metabolic modulator rules change.
A note for anyone sourcing it
Mazdutide sold as "research chemical" material is not the approved pharmaceutical product. Anything not dispensed through a regulated channel carries no guarantee of identity, purity, or correct fill. If you are looking at a vendor, the things that actually matter are independent third-party testing: a recent certificate of analysis tied to the specific lot, confirming both identity (that it is mazdutide and not a cheaper GLP-1 peptide) and purity, ideally by mass spectrometry and HPLC. peptideone aggregates the third-party raters and published COAs we can find so those claims can be checked rather than taken on trust.
This page is informational and aggregates public facts with attribution. It is not medical or dosing advice, and nothing here is a recommendation to use mazdutide outside an approved clinical setting.
Sources
- Innovent / PR Newswire, NMPA approval for chronic weight management (June 2025)
- New England Journal of Medicine via Innovent, GLORY-1 phase 3 publication (May 2025)
- eClinicalMedicine (The Lancet), phase 1b trial of mazdutide IBI362 (2022)
- Wikipedia, Mazdutide (identity, development history, originator codes)