Mazdutide (LY3305677, IBI362)
Investigational GLP-1 / glucagon dual agonist developed by Eli Lilly and Innovent Biologics, primarily advancing in China.
At a glance
What it is: Investigational GLP-1 / glucagon dual agonist developed by Eli Lilly and Innovent Biologics, primarily advancing in China..
Primary research applications:
- Obesity
- Type 2 diabetes
- MASH
Editorial summary: Mazdutide is a dual GLP-1 / glucagon agonist with Phase 3 obesity data from the GLORY-1 program in China showing up to ~14% weight loss at 48 weeks. Approval pathways are advancing in China; global availability remains uncertain.
- Class / structure
- Synthetic peptide co-agonist; oxyntomodulin-derived backbone
- Half-life
- Designed for once-weekly dosing
- First described
- Late 2010s
- Regulatory status
- Approved in China (2025); investigational elsewhere
What is Mazdutide?
Mazdutide is an investigational synthetic peptide that activates both GLP-1 and glucagon receptors, mimicking and extending the action of endogenous oxyntomodulin.
Discovery and development
Mazdutide originated from Eli Lilly's oxyntomodulin-class research and is being co-developed in China by Innovent Biologics. Its design draws on oxyntomodulin biology — an endogenous gut hormone with combined GLP-1 and glucagon receptor activity that has long been studied as a model for the dual-agonist concept.
Mechanism of action
GLP-1 agonism contributes appetite suppression, slowed gastric emptying, and glucose-dependent insulin secretion. The glucagon arm adds energy expenditure and hepatic lipid handling. The relative receptor balance is engineered to favor weight loss while maintaining glycemic control.
Pharmacokinetics
Mazdutide is given as a weekly subcutaneous injection. Its molecular design supports a half-life consistent with weekly dosing.
What the research shows
The peer-reviewed literature on Mazdutide is summarized below across two tiers: human research (the highest standard), and preclinical / emerging research (animal models and early-stage human work).
Claims and the evidence behind them
This table summarizes commonly discussed claims and how the published evidence weighs in. The aim is clarity — supported claims, claims that look promising but need more data, and claims that outrun the science.
| Claim | What the evidence shows | Verdict |
|---|---|---|
| Produces ~14% weight loss at Phase 3 | GLORY-1 | Supported |
| Approved for obesity in China | 2025 Chinese NMPA approval | Supported |
| Approved in the US/EU | Not as of early 2026 | Unsupported |
Reported user experiences
How the research describes administration
Once-weekly subcutaneous injection with stepped titration to the trial's maintenance dose.
Editorial note
Administration details above describe how the peptide is given in published studies. We summarize this for educational completeness — these descriptions are not protocols, dosing recommendations, or instructions for personal use. Decisions about treatment require an appropriately licensed clinician.
Safety considerations and open questions
The takeaway
Mazdutide is significant as the first GLP-1/glucagon dual agonist approved for obesity in any major regulatory jurisdiction (China, 2025). Its place in the broader incretin landscape will depend on Western regulatory progress and the still-unfolding outcomes data for the dual-agonist class as a whole.
Frequently asked questions
Is mazdutide available in the US?
Not as of early 2026. Its lead regulatory pathway has been in China.
How does mazdutide differ from retatrutide?
Mazdutide is a dual GLP-1 / glucagon agonist; retatrutide is a triple GLP-1 / GIP / glucagon agonist. Retatrutide's Phase 2 weight loss exceeded mazdutide's Phase 3, but they are at different development stages.
References
- Innovent Biologics / Eli Lilly. Mazdutide GLORY-1 Phase 3 results in obesity (Chinese regulatory submission and corporate disclosure, 2024–2025). Peer-reviewed publication pending. https://pubmed.ncbi.nlm.nih.gov/?term=mazdutide
- Ji L, et al. A Phase 2 randomised controlled trial of mazdutide in Chinese overweight adults or adults with obesity. Nat Commun. 2023;14:8289. https://pubmed.ncbi.nlm.nih.gov/?term=mazdutide+phase+2
- Pocai A, et al. Glucagon-like peptide 1/glucagon receptor dual agonism reverses obesity in mice. Diabetes. 2009;58(10):2258-2266. (Foundational dual-agonist mechanism.) https://pubmed.ncbi.nlm.nih.gov/19602537/