Compounds / Mazdutide
Mazdutide
Also known as: IBI362; LY3305677; GLP-1/glucagon receptor dual agonist; oxyntomodulin analog
Primary research focus: Obesity and type 2 diabetes (metabolic); approved in China, investigational in the US
Last updated July 2026 · Reviewed against FDA labeling and published research.
What is Mazdutide?
Mazdutide is a once-weekly injectable peptide that activates both the GLP-1 receptor and the glucagon receptor, making it the first dual GLP-1/glucagon agonist approved anywhere for weight management. It is a long-acting synthetic analog of oxyntomodulin, a natural gut hormone, with a fatty-acyl modification to extend its half-life. It was developed by Innovent Biologics with Eli Lilly and was approved in China in June 2025; it is not FDA-approved and remains investigational in the United States.
Mazdutide is an analog of mammalian oxyntomodulin and binds both the GLP-1 receptor and the glucagon receptor. GLP-1 receptor agonism enhances glucose-dependent insulin secretion, slows gastric emptying, and reduces appetite; glucagon receptor agonism is intended to increase energy expenditure and enhance fat oxidation and hepatic lipid handling. Preclinical work showed mazdutide reduced body weight in both glucagon-receptor and GLP-1-receptor knockout mice, indicating both arms contribute, and unlike semaglutide it increased energy expenditure. A fatty-acyl moiety extends its half-life to allow once-weekly dosing.
How it’s supplied
Approved and marketed in China as a once-weekly subcutaneous injection for weight management. It is not FDA-approved or commercially available in the United States, where it remains investigational and is available only through clinical trials. Material sold outside those channels is gray-market research product, not FDA-reviewed for potency or sterility.
Dosage Chart
Units shown are for a U-100 insulin syringe (100 units = 1 mL), calculated from the vial size and BAC water you select. Always confirm against your prescription and your syringe markings.
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Weeks 1-4 | 2.5mg | 1x Weekly | — |
| Weeks 5+ | 5mg | 1x Weekly | — |
- Administer on the same day each week to maintain stable plasma levels
- Titrate slowly; gastrointestinal effects are dose-related and ease with gradual escalation
- Rotate injection sites to reduce irritation and lipohypertrophy
- Reduce dose when combined with insulin or sulfonylureas to lower hypoglycemia risk
- Discuss pausing before scheduled surgery or anesthesia (delayed gastric emptying)
- Maintain hydration to offset gastrointestinal fluid loss
- Not for use during pregnancy or breastfeeding
- Do not exceed the recommended dose to try to speed results
Potential Benefits and Side Effects
Effects reported in published research. Not a promise of results, and not medical advice.
- Reported in clinical trials (largely Chinese populations); not a US approved-label claim.
- Approximately 14.8 percent average weight loss at 48 weeks with the 6 mg dose in the Phase 3 GLORY-1 trial.
- Improved glycemic control in type 2 diabetes trials.
- Increased energy expenditure via glucagon receptor agonism, in addition to GLP-1 appetite reduction.
- Reported benefits for hepatic fat and metabolic dysfunction-associated fatty liver measures.
- Reported effects are primarily gastrointestinal and consistent with the incretin drug class.
- Nausea.
- Vomiting.
- Diarrhea.
- Decreased appetite.
- Gastrointestinal effects are dose-dependent and most common during escalation; heart-rate increase is a consideration with glucagon agonism.
Warnings and contraindications
Important safety information. This is not exhaustive — read the full prescribing information and consult your prescriber or pharmacist.
- No FDA-approved labeling exists; the following reflect trial observations and class effects, not a US label.
- Mazdutide is not FDA-approved; its US safety profile will be defined through FDA review, and no published safety data from US populations or from trials longer than 32 weeks were available as of early 2026.
- Gastrointestinal effects are the most common class effect and are dose-dependent, typically during dose escalation.
- Glucagon receptor agonism can raise heart rate and may increase hepatic glucose output, warranting attention in trials.
- GLP-1 class considerations include pancreatitis, gallbladder events, and caution with a history of medullary thyroid carcinoma or MEN 2.
- Gray-market material varies in identity and purity; safety in pregnancy and breastfeeding has not been established.
- Not established as a US-approved product; contraindications will be defined at any FDA approval. Class-based cautions for GLP-1-containing agents include personal or family history of medullary thyroid carcinoma, MEN 2, and known hypersensitivity.
Reconstitution Steps
How to prepare the lyophilized vial. Confirm specifics with your pharmacist or prescriber.
- Confirm the amount of peptide in the vial and the volume of diluent you intend to use before starting.
- Wash your hands and gather supplies: the lyophilized vial, the diluent (typically bacteriostatic water), an alcohol swab, and a sterile syringe.
- Let the vial and diluent reach room temperature if they were refrigerated or frozen.
- Wipe the rubber stopper of both the peptide vial and the diluent vial with a fresh alcohol swab and let them air dry.
- Draw the intended diluent volume into the syringe.
- Insert the needle into the vial and slowly release the diluent down the inside wall rather than directly onto the powder, to avoid foaming.
- Do not shake. Gently swirl or roll the vial until fully dissolved.
- Inspect the solution: it should be clear and colorless with no visible particles. Do not use if cloudy or containing particles.
- Note the resulting concentration (amount divided by diluent volume) so it matches the reconstitution calculator on this page.
- Label the vial with the reconstitution date and store as directed under reconstituted storage.
US regulatory status
Classifications are public record but can change. For reference only, not legal advice.
Development: Mazdutide was developed by Innovent Biologics (China rights) under license from Eli Lilly (global rights), and is also known as IBI362 and LY3305677. Early Chinese Phase 1b trials (Ji et al., eClinicalMedicine 2021; Jiang et al., 2022) established safety and dose-dependent weight loss, with 12-week reductions up to approximately 6.4 percent at doses up to 6 mg. The Phase 3 GLORY-1 trial in Chinese adults with overweight or obesity reported approximately 14.8 percent average weight loss at 48 weeks with the 6 mg dose versus about 0.5 percent for placebo. In June 2025 mazdutide was approved for marketing in China, making it the first GLP-1/glucagon dual receptor agonist approved for weight management anywhere. US development is at an earlier stage: Eli Lilly has run a Phase 2 trial in a US population (NCT06143956), and as of mid-2026 no NDA had been submitted to the FDA.
Notes: Mazdutide is approved in China (June 2025) for weight management but is not FDA-approved and is investigational in the United States, where no NDA had been submitted as of mid-2026. Because it is investigational in the US, there is no legal prescriber or compounding pathway outside a clinical trial; it is not on the FDA 503A bulk drug substances list and is not eligible for 503A or 503B compounding. Products sold under this name in the US are unregulated research chemicals. It is not a controlled substance. (Status current as of mid-2026.)
International status
Pharmacokinetics
Storage and handling
Important Notes
Practical considerations for consistency and safety.
- Mazdutide is approved in China but NOT FDA-approved; US status is investigational, with no NDA submitted as of mid-2026.
- It is the first GLP-1/glucagon dual receptor agonist approved for weight management anywhere.
- Its glucagon arm is intended to add energy expenditure, a mechanism GLP-1-only drugs lack.
- Published efficacy comes from Chinese trial populations; US and longer-term data are limited.
- Gray-market material varies in identity and purity.
Lifestyle Factors
- Studied together with diet and physical activity for weight management.
- Adequate hydration can reduce dehydration-related complications during gastrointestinal side effects.
References
Related compounds
Important disclaimer
This page is an educational reference, not medical advice, a diagnosis, or a treatment recommendation, and not a substitute for your prescriber or pharmacist. Approval and regulatory status varies by compound and can change. Always confirm against current prescribing information and consult a qualified healthcare professional before making any decision about a medication.