Mazdutide is a once-weekly injectable drug that activates two metabolic receptors at the same time, the GLP-1 receptor and the glucagon receptor. That dual action is what sets it apart from the GLP-1-only drugs most people already know, such as semaglutide (Ozempic, Wegovy). In June 2025 mazdutide became the first dual glucagon/GLP-1 receptor agonist approved anywhere in the world for chronic weight management, when China's National Medical Products Administration (NMPA) cleared it for adults with obesity or overweight.[1] It is not approved by the U.S. Food and Drug Administration. This guide covers what mazdutide is, how it works, the dosage used in trials, its side effects, the real-world weight-loss numbers, and the legal reality of buying it in the United States.
🔑 Key Takeaways
- Mazdutide is a dual glucagon (GCG) and GLP-1 receptor agonist built on the gut hormone oxyntomodulin. The added glucagon activity is meant to raise energy expenditure and cut liver fat on top of standard GLP-1 appetite suppression.[1][4]
- In the Phase 3 GLORY-2 trial, the 9 mg dose produced about 18.6% mean weight loss overall and 20.1% in participants without type 2 diabetes at 60 weeks, with no plateau seen by the end of the study.[2]
- In a head-to-head Phase 3 trial (DREAMS-3), mazdutide 6 mg beat semaglutide 1 mg for combined blood sugar and weight goals in people with type 2 diabetes and obesity.[3]
- The main side effects are gastrointestinal, nausea, diarrhea, vomiting, and reduced appetite, mostly mild to moderate and most common during dose increases.[5]
- Mazdutide is approved only in China. It is not FDA approved, and the FDA has issued warning letters naming mazdutide as an unapproved new drug when sold by U.S. research-peptide vendors.[7]
What Is Mazdutide?
Mazdutide (development codes IBI362 from Innovent Biologics and LY3305677 from Eli Lilly) is a synthetic analog of oxyntomodulin, a naturally occurring gut hormone released after eating.[6] Oxyntomodulin is unusual because it stimulates both the GLP-1 receptor and the glucagon receptor. Mazdutide copies that dual signaling in a long-acting, fatty-acid-modified peptide that can be injected once a week.[4]
It was co-developed by Innovent Biologics and Eli Lilly, with Innovent holding the rights in China.[6] In China it is marketed for chronic weight management in adults with a body mass index (BMI) of 28 kg/m² or higher (obesity), or 24 kg/m² or higher (overweight) with at least one weight-related health condition.[1] China later granted a separate approval for blood sugar control in type 2 diabetes.[3]
If you are new to this drug class, our overview of GLP-1 medications and our explainer on how the GLP receptor subtypes differ are useful background. Mazdutide also appears in our broad comparison of tirzepatide versus every GLP-1 drug.
How Does Mazdutide Work?
Most weight-loss drugs in this category, including semaglutide, act only on the GLP-1 receptor. GLP-1 activation slows stomach emptying, increases the sense of fullness, and improves insulin release, which together reduce how much you eat.[9] Mazdutide adds a second mechanism by also switching on the glucagon receptor.
Glucagon is best known for raising blood sugar, but at the doses used here its receptor activity is thought to do something useful for body composition: increase resting energy expenditure (the calories you burn at rest) and push the liver to burn stored fat.[1] The GLP-1 component offsets glucagon's blood-sugar-raising tendency, so the net effect in trials has been lower glucose, not higher.[3] In practice this combination has produced large reductions in liver fat content, with the 6 mg dose cutting liver fat by roughly 80% in people who started with high liver fat in the GLORY-1 trial.[1]
Why "dual agonist" matters
Think of GLP-1 as the "eat less" lever and glucagon as the "burn more" lever. Single-agonist drugs pull only the first lever. Mazdutide pulls both at once, which is the rationale for its strong effect on visceral and liver fat. This is a different combination from tirzepatide, which pairs GLP-1 with GIP rather than glucagon, and from retatrutide, which adds glucagon on top of both GLP-1 and GIP.[1]
Mazdutide Dosage (As Used in Trials)
The doses below come from the clinical trials and the Chinese label. There is no FDA-approved mazdutide dosing in the United States. Dosing should only ever be directed by a licensed prescriber.
Mazdutide is given as a once-weekly subcutaneous injection and is titrated slowly to limit nausea. China approved the 4 mg and 6 mg strengths for weight management, reaching the maintenance dose with a short, 2-step titration.[1] The 9 mg dose studied in GLORY-2 is the highest tested for obesity and is notable for reaching full strength in just two titration steps.[2]
| Setting | Doses studied / approved | Schedule | Notes |
|---|---|---|---|
| Phase 2 (obesity) | 3 mg, 4.5 mg, 6 mg | Once weekly, 24 weeks | Dose-dependent weight loss; all beat placebo[5] |
| GLORY-1 (Phase 3, obesity) | 4 mg, 6 mg | Once weekly, 48 weeks | Basis for China approval[1] |
| GLORY-2 (Phase 3, obesity) | 9 mg | Once weekly, 60 weeks, 2-step titration | Highest dose tested for obesity[2] |
| DREAMS-3 (Phase 3, T2D) | 6 mg | Once weekly, 32 weeks | Compared head-to-head with semaglutide 1 mg[3] |
| China label (weight) | 4 mg and 6 mg | Once weekly maintenance | Reached after 2-step titration[1] |
Mazdutide Results: What the Trials Actually Showed
Mazdutide has been studied across a clear dose ladder, from a small Phase 1b study through two large Phase 3 obesity trials (GLORY-1 and GLORY-2) and a head-to-head diabetes trial against semaglutide (DREAMS-3).
GLORY-1 (4 mg and 6 mg)
In the GLORY-1 Phase 3 trial, at week 48 the 6 mg dose produced a mean body-weight reduction of 14.8%, the 4 mg dose 12.0%, versus a 0.5% drop with placebo.[1] Roughly half of participants on 6 mg (50.6%) lost at least 15% of their body weight, compared with 2.1% on placebo.[1] Waist circumference fell by about 11.0 cm (4.3 in) on 6 mg, and among people with high baseline liver fat, the 6 mg group reduced liver fat content by about 80%.[1]
GLORY-2 (9 mg)
GLORY-2 tested the higher 9 mg dose in 462 adults (mean weight about 94 kg, or 207 lb; mean BMI 34.3) over a 60-week double-blind period.[2] Mean weight loss was 18.6% across the whole mazdutide group and 20.1% in participants without type 2 diabetes, against about 3% with placebo.[2] Among everyone treated, 44.0% lost at least 20% of their body weight, versus 2.6% on placebo. Importantly, weight was still declining at week 60 with no plateau.[2] Mazdutide also improved waist circumference, systolic blood pressure, triglycerides, LDL and non-HDL cholesterol, and serum uric acid.[2]
DREAMS-3 (head-to-head vs semaglutide)
DREAMS-3 randomized 349 adults with type 2 diabetes and obesity to mazdutide 6 mg or semaglutide 1 mg for 32 weeks.[3] On the combined target of HbA1c below 7% plus at least 10% weight loss, 48.0% of the mazdutide group hit both goals versus 21.0% on semaglutide. Average weight loss was 10.29% with mazdutide versus 6.0% with semaglutide, and HbA1c fell by 2.03% versus 1.84%.[3]
Effect size in real terms
Percentages are abstract, so here is what the trial averages translate to for a person who weighs 200 lb (about 91 kg). These are illustrative conversions of the published mean percentages, not predictions for any individual.
| Dose / trial | Mean % loss | Pounds lost (200 lb start) | Kilograms lost (91 kg start) |
|---|---|---|---|
| 4 mg, GLORY-1, 48 wk | 12.0% | ~24 lb | ~10.9 kg |
| 6 mg, GLORY-1, 48 wk | 14.8% | ~30 lb | ~13.5 kg |
| 9 mg, GLORY-2, 60 wk (overall) | 18.6% | ~37 lb | ~16.9 kg |
| 9 mg, GLORY-2, 60 wk (no T2D) | 20.1% | ~40 lb | ~18.3 kg |
For context on how this stacks up against drugs you can actually get prescribed in the U.S., see our semaglutide vs tirzepatide comparison and our roundup of every FDA-approved weight-loss injection.
How Mazdutide Compares to Other Weight-Loss Peptides
Mazdutide sits in a crowded field of incretin-based drugs. The key differences are which receptors each one targets and where each stands with regulators. The figures below are mean weight-loss results from each drug's pivotal program and are not from a single head-to-head study, so treat cross-trial comparisons as directional only.
| Drug | Receptors | Peak trial weight loss | Dosing | U.S. status |
|---|---|---|---|---|
| Mazdutide | GLP-1 + glucagon (dual) | ~20% (9 mg, 60 wk)[2] | Weekly injection | Not FDA approved (China only)[1] |
| Semaglutide (Wegovy) | GLP-1 only | ~15% (STEP program) | Weekly injection | FDA approved |
| Tirzepatide (Zepbound) | GLP-1 + GIP (dual) | ~21% (SURMOUNT-1) | Weekly injection | FDA approved |
| Retatrutide | GLP-1 + GIP + glucagon (triple) | ~24% (Phase 3 TRIUMPH-1) | Weekly injection | Investigational |
| Survodutide | GLP-1 + glucagon (dual) | ~19% (Phase 2) | Weekly injection | Investigational |
For deeper dives, see our guides on survodutide (the other major GLP-1/glucagon dual agonist), retatrutide's TRIUMPH-1 results, and CagriSema.
Mazdutide Side Effects
Like every drug in this class, mazdutide's most common side effects are gastrointestinal. In the Phase 2 trial the most frequent were nausea (about 21% to 41% depending on dose), diarrhea (19% to 31%), vomiting (13% to 28%), and decreased appetite (10% to 30%).[5] These were mostly mild to moderate and tended to appear during dose escalation, then settle.
In the larger GLORY-2 trial, gastrointestinal events were again described as mild to moderate and transient, with only 2.9% of the mazdutide group stopping treatment because of side effects (versus 0% on placebo), and no new safety signals identified.[2] The early Phase 1b study also logged upper respiratory and urinary tract infections, abdominal distension, and reduced appetite, all mild or moderate.[8]
Because mazdutide activates the glucagon receptor, heart rate and blood pressure are monitored in trials; published Phase 3 data showed systolic blood pressure improved rather than worsened.[2] As with all GLP-class drugs, the labeling concerns for related agents include pancreatitis, gallbladder problems, and a boxed thyroid C-cell tumor warning seen with GLP-1 drugs in rodents.[9] For class-wide context, see our guides on tirzepatide side effects and retatrutide side effects.
Who is studying mazdutide for, and who is it not for
In its Chinese trials and label, mazdutide is intended for adults with obesity (BMI 28+) or overweight (BMI 24+) plus a weight-related condition, and separately for type 2 diabetes.[1][3] Like other GLP-class drugs, it is not appropriate during pregnancy or breastfeeding, and the class carries a contraindication for people with a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome.[9] It is not a cosmetic "few pounds" drug, and it is not a substitute for a medically supervised plan. Anyone with diabetes, gallbladder disease, pancreatitis history, or who is taking other glucose-lowering drugs should only use an incretin therapy under a prescriber's care.
Is Mazdutide Legal?
This is the part that trips people up. Mazdutide is approved in China, but it is not approved by the U.S. FDA for any use, and no U.S. marketing application has cleared.[6] That means it cannot be legally sold for human use in the United States.
The "research use only" or "not for human consumption" labels used by gray-market peptide vendors do not make selling mazdutide legal. In March 2026 the FDA issued a warning letter that explicitly named mazdutide among the products a U.S. vendor was marketing as an unapproved new drug, alongside other GLP-class compounds.[7] Importing unapproved drugs for personal use is also restricted; the FDA's personal-importation policy rarely covers products like this, and shipments can be detained or refused.[10]
If your goal is medically supervised weight loss in the U.S. today, the realistic options are the FDA-approved drugs (semaglutide and tirzepatide) through a licensed provider. Our guides on the best online GLP-1 programs and the cheapest GLP-1 options walk through legitimate access routes. The NIDDK also maintains a plain-language list of approved obesity medications for reference.[11]
The Bottom Line
Mazdutide is one of the most promising next-generation obesity drugs, and its first-in-class dual GLP-1/glucagon mechanism delivered up to about 20% weight loss with strong improvements in liver fat, blood pressure, lipids, and blood sugar in Phase 3 trials.[1][2][3] But as of mid-2026 it is approved only in China. In the United States it remains investigational and is not legal to sell for human use, and any product marketed here is unapproved.[6][7] If and when Eli Lilly pursues U.S. development, mazdutide could become a meaningful option, but for now the safe, legal path is an FDA-approved GLP-1 or GLP-1/GIP drug prescribed and monitored by a clinician.
Frequently Asked Questions
References
- Innovent Biologics. Mazdutide, First Dual GCG/GLP-1 Receptor Agonist, Received Approval from China's NMPA for Chronic Weight Management (PRNewswire, June 2025).
- Innovent Biologics. Mazdutide 9 mg Achieves Up to 20.1% Weight Loss in Chinese Adults with Obesity, GLORY-2 (PRNewswire, 2025).
- Innovent Biologics. Mazdutide Shows Superiority over Semaglutide in Head-to-Head Phase 3 Trial DREAMS-3 (PRNewswire, October 2025).
- Mazdutide: First Approval. Drugs (Springer), 2025. doi:10.1007/s40265-025-02249-y.
- Ji L, et al. A phase 2 randomised controlled trial of mazdutide in Chinese overweight adults or adults with obesity. PMC10719339.
- Mazdutide (drug class, developers, identifiers, regulatory status). Wikipedia.
- U.S. Food and Drug Administration. Warning Letter, Prime Sciences (March 31, 2026), naming mazdutide as an unapproved new drug.
- Phase 1b multiple-ascending-dose trial of mazdutide (IBI362) 9 mg and 10 mg in Chinese adults with overweight or obesity. PMC9561728.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Prescription Medications to Treat Overweight and Obesity.
- U.S. Food and Drug Administration. Personal Importation policy.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Weight Management overview.