Mazdutide is a once-weekly injectable peptide that activates both the GLP-1 receptor and the glucagon receptor. Developed by Innovent Biologics under license from Eli Lilly, it was approved in China in 2025 for chronic weight management and, separately, for glycemic control in type 2 diabetes. It has not been approved anywhere else, and Eli Lilly, which holds rights outside China, has only reached phase 2 in the United States.
Research snapshot
| Category | Current information |
|---|---|
| Peptide category | Dual GLP-1 / glucagon (GCG) receptor agonist (oxyntomodulin analogue) |
| Primary research interest | Chronic weight management; glycemic control in type 2 diabetes |
| Highest available evidence | Tier 1 – multiple published/peer-reviewed phase 3 trials supporting Chinese regulatory approval |
| Human research available | Yes – phase 3 programme of several thousand participants, entirely in China |
| Development status | Approved in China (Innovent Biologics, under license from Eli Lilly); phase 2 only in the US |
| Regulatory status | NMPA-approved (China) for weight management (June 2025) and type 2 diabetes (September 2025); not approved in the US, EU, or UK |
| Last reviewed | 2026 |
Technical identity
| Technical property | Information |
|---|---|
| Primary name | Mazdutide |
| Alternative names | IBI362, LY3305677 (code names), mazdutide acetate |
| Peptide sequence | 39 amino acid oxyntomodulin-analogue peptide with a C-18 fatty diacid side chain for albumin binding |
| Amino-acid length | 39 residues |
| Molecular formula | C210H322N46O67 |
| Molecular weight | 4563.14 g/mol |
| CAS Registry Number | 2259884-03-0 |
| PubChem CID | 167312357 |
| Chemical modifications | C-18 fatty diacid conjugation via linker, promoting albumin binding for once-weekly dosing |
| Peptide class | Oxyntomodulin analogue, dual GLP-1/glucagon receptor agonist |
| Primary biological target | GLP-1 receptor and glucagon receptor (balanced activation) |
| Developer or originator | Innovent Biologics, co-developed with Eli Lilly |
| Development status | Approved in China; phase 2 in the US |
What it is
Mazdutide (development codes IBI362 and LY3305677) is a 39 amino acid synthetic peptide modeled on oxyntomodulin, a natural gut hormone that activates both the GLP-1 receptor and the glucagon receptor. A fatty acid side chain lets it bind albumin in the blood, extending its action to support once-weekly dosing. Innovent Biologics and Eli Lilly co-developed it, with Innovent leading commercialization in China. China’s National Medical Products Administration approved it in June 2025 for chronic weight management and in September 2025 for glycemic control in type 2 diabetes, the first approvals anywhere for a dual GCG/GLP-1 receptor agonist. It is not approved in the United States, the European Union, or any other market as of September 2026; Eli Lilly is developing it separately outside China and has completed only a phase 2 trial there.
How does it work?
Plain-English explanation
Mazdutide mimics two hormones at once. Like semaglutide and tirzepatide, it activates the GLP-1 receptor, which slows stomach emptying, reduces appetite, and helps the pancreas release insulin when blood sugar is high. It also activates the glucagon receptor, which increases the amount of energy the body burns at rest. The idea, shared with survodutide and pemvidutide, is that combining appetite reduction with a modest metabolic boost produces more weight loss than appetite reduction alone.
Technical explanation
Mazdutide is an oxyntomodulin analogue engineered for balanced activity at the human GLP-1 and glucagon receptors, in contrast to tirzepatide, which is GLP-1/GIP, and retatrutide, which adds a third receptor. A C-18 diacid fatty chain conjugated through a linker promotes albumin binding, giving it a half-life compatible with once-weekly subcutaneous dosing. Unlike liraglutide or semaglutide, it is not a modified GLP-1 molecule; it is built on the oxyntomodulin backbone, which is the structural reason it carries native glucagon-receptor activity rather than none at all.
Potential benefits and research applications
Weight loss in people with obesity or overweight
What is being investigated: whether combining GLP-1 and glucagon receptor activation produces greater weight loss than GLP-1 activation alone. How the effect might occur: appetite suppression from the GLP-1 arm combined with increased resting energy expenditure from the glucagon arm. Evidence: the phase 3 GLORY-1 trial in 610 Chinese adults with obesity or overweight showed mean weight loss of 12.05 percent at 4 mg and 14.84 percent at 6 mg over 48 weeks, against 0.47 percent on placebo. A separate phase 3 trial in more severe obesity (BMI 30 or higher) using a 9 mg dose over 60 weeks reported 18.55 percent mean weight loss, with 44.0 percent of participants losing 20 percent of body weight or more. Strength: has been shown in two large, peer-reviewed or company-reported phase 3 trials. Limitation: both trials enrolled only Chinese adults, so how the results generalize to other populations has not been directly tested, and the 9 mg trial’s full results have not yet appeared in a peer-reviewed journal as of this writing.
Glycemic control in type 2 diabetes
What is being investigated: HbA1c reduction and weight loss in adults with type 2 diabetes, both as monotherapy and added to metformin or sulfonylureas. How the effect might occur: the GLP-1 arm’s insulin-secretion and appetite effects, standard for this drug class. Evidence: this is the basis of mazdutide’s September 2025 NMPA approval for glycemic control, supported by phase 3 data including a 28-week head-to-head trial (DREAMS-2) in which mazdutide 4 mg and 6 mg both showed statistically superior HbA1c and weight results compared with dulaglutide 1.5 mg in 731 participants, and by two phase 3 trials against placebo published back-to-back in Nature. Strength: has been shown in multiple published or peer-reviewed phase 3 trials leading to formal regulatory approval. Limitation: the approval and evidence base are specific to the Chinese population and the Chinese regulator; no comparable review has been completed by the FDA or EMA.
Liver fat, blood pressure, and lipid improvements (as a byproduct of weight loss)
What is being investigated: reductions in liver fat content, blood pressure, triglycerides, LDL cholesterol, and uric acid alongside weight loss. How the effect might occur: largely secondary to substantial weight reduction, a pattern shared across the GLP-1/glucagon and GLP-1/GIP drug class. Evidence: in the GLORY-1 and GLORY-2 trials, participants with elevated baseline liver fat saw reductions of roughly 63 to 74 percent by MRI, alongside improvements in waist circumference, systolic blood pressure, triglycerides, LDL cholesterol, and serum uric acid. Strength: has been shown in phase 3 imaging and laboratory substudies. Limitation: like the retatrutide and semaglutide liver findings, these are imaging and biomarker changes, not liver biopsy-confirmed resolution of steatohepatitis, and no dedicated liver-outcome trial for mazdutide has been published.
What dosage information circulates?
Figures in this section summarize amounts and schedules reported in published research or circulating online. Their inclusion documents what is reported and does not establish that a regimen is verified, safe, effective, or appropriate.
Every dose of mazdutide with published human data comes from company-sponsored, peer-reviewed or company-reported phase 3 trials conducted in China, all using once-weekly subcutaneous injection with a titration period before reaching a fixed maintenance dose. No independent, non-company dosing data exist, and no dosing outside these approved indications has been studied in a controlled trial.
| Reported use or research objective | Route reported | Amount reported | Frequency reported | Reported duration | Evidence or source category |
|---|---|---|---|---|---|
| GLORY-1, obesity/overweight (China, approved) | Subcutaneous | 4 mg or 6 mg | Once weekly, titrated | 48 weeks | Published human clinical trial (NEJM) |
| Higher-BMI trial (company designation “GLORY-2”) | Subcutaneous | 9 mg, two-step titration | Once weekly | 60 weeks | Company-reported phase 3 (not yet peer-reviewed) |
| DREAMS-2, type 2 diabetes (China, approved) | Subcutaneous | 4 mg or 6 mg | Once weekly | 28 weeks | Company-reported phase 3 (head-to-head vs. dulaglutide) |
All published dosing data come from company-sponsored trials conducted exclusively in Chinese adults. No independent academic trial, and no trial in a non-Chinese population, has been identified.
Amounts studied in human research
GLORY-1 (NEJM), the pivotal obesity and overweight trial, randomised 610 adults with obesity (BMI 28 or higher) or overweight (BMI 24-28) with at least one weight-related comorbidity to mazdutide 4 mg once weekly, 6 mg once weekly, or placebo, for 48 weeks, reaching mean weight reductions of 12.05 and 14.84 percent respectively against 0.47 percent on placebo.
A second phase 3 trial (referred to in company communications as GLORY-2) enrolled 462 adults with BMI 30 or higher, 16 percent of whom had type 2 diabetes, and used a 9 mg once-weekly maintenance dose reached through what the sponsor describes as a two-step dose titration, over 60 weeks, reaching 18.55 percent mean weight loss overall and 20.08 percent in participants without diabetes.
DREAMS-2, a head-to-head phase 3 trial in 731 adults with type 2 diabetes, compared mazdutide 4 mg and 6 mg once weekly against dulaglutide 1.5 mg once weekly over 28 weeks, reporting statistical superiority on HbA1c and weight change for both mazdutide doses; the sponsor’s press release did not disclose the numeric HbA1c or weight changes.
Two further phase 3 trials in type 2 diabetes, comparing mazdutide against placebo, were published together in Nature; exact per-arm dose and outcome figures from those two papers were not independently retrieved for this entry and are not reproduced here to avoid restating unverified numbers.
Practitioner and community-reported protocols
Not consistently reported. Because mazdutide is approved and sold only in China and has not reached the compounding or grey-market research-chemical channels common to semaglutide, tirzepatide, or retatrutide, this site did not identify an established community-reported dosing pattern for mazdutide outside its labeled use as of September 2026.
Side effects, risks, and limitations
Across the phase 3 obesity trials, the most frequently reported adverse events were gastrointestinal: nausea, diarrhea, and vomiting, described as mostly mild to moderate and transient. Heart rate rose modestly (about 2.6 beats per minute) in the GLORY-1 mazdutide arms, without a reported cardiovascular safety signal. In the 9 mg, 60-week trial, 2.9 percent of participants discontinued for adverse events against none on placebo. As with every drug in this class, long-term cardiovascular and cancer outcome data are limited relative to older diabetes drugs, and mazdutide has not been tested for as long, in as many people, or in as many countries as semaglutide or liraglutide.
Regulatory and developmental status
Mazdutide is approved by China’s NMPA for two indications: chronic weight management (June 2025, for adults who are overweight or obese with at least one weight-related comorbidity) and glycemic control in type 2 diabetes (September 2025, as monotherapy or combined with metformin, sulfonylureas, or SGLT2 inhibitors). It is not approved in the United States, the European Union, the United Kingdom, or any other jurisdiction identified for this entry. Eli Lilly, which holds development and commercialization rights outside China, has reported only a phase 2 trial in the United States; no phase 3 programme or regulatory filing outside China had been confirmed as of September 2026.
Frequently asked questions
What is mazdutide?
A once-weekly injectable peptide that activates both the GLP-1 and glucagon receptors, approved in China for chronic weight management and for type 2 diabetes. It is not approved in the United States or Europe.
How does it work?
It combines a GLP-1 receptor effect, which reduces appetite and slows digestion, with a glucagon receptor effect, which modestly raises resting energy expenditure, an approach it shares with survodutide and pemvidutide.
What dosage has been studied?
Phase 3 trials used 4 mg, 6 mg, and 9 mg once weekly by subcutaneous injection, each reached through a titration period before the trial’s fixed maintenance dose.
What dosage commonly circulates online?
Not consistently reported. Mazdutide has not shown up in the same grey-market research-chemical channels as semaglutide, tirzepatide, or retatrutide, likely because its approved supply chain runs through China rather than through peptide vendors sourcing from Western clinical trial leftovers or synthesis labs.
How much weight loss has been shown?
Mean weight loss of 12.05 percent at 4 mg and 14.84 percent at 6 mg over 48 weeks in one phase 3 trial, and 18.55 percent at 9 mg over 60 weeks in another, all against roughly 0 to 2.6 percent on placebo.
Has it been studied in humans?
Yes, in a phase 3 programme of several thousand participants in China spanning obesity, overweight, and type 2 diabetes, leading to two separate NMPA approvals.
Is it approved in the United States?
No. It is approved only in China. Eli Lilly holds rights outside China and has reported only a phase 2 trial in the United States as of September 2026.
What side effects have been reported?
Mostly gastrointestinal: nausea, diarrhea, and vomiting, generally mild to moderate. A modest increase in heart rate was also reported, without an identified cardiovascular safety signal in the trials conducted so far.
What remains unknown?
Long-term cardiovascular and cancer outcomes, safety and efficacy outside the Chinese population studied in its pivotal trials, and whether or when it will be reviewed by the FDA or EMA.
Bottom line
Mazdutide is a dual GLP-1/glucagon receptor agonist with a genuine, publicly documented phase 3 record and two real regulatory approvals in China, one for weight management and one for type 2 diabetes. Its weight-loss figures (roughly 12 to 19 percent depending on dose and trial) are credible and peer-reviewed or company-reported, but the entire evidence base to date comes from Chinese trial populations, and it remains unapproved and comparatively under-studied everywhere else, including the United States. It has not shown up in the community and grey-market research-chemical circulation seen with semaglutide, tirzepatide, or retatrutide.