Description
PrymaLab · Research use only
Mazdutide 10mg
Mazdutide (IBI362, LY3305677), an acylated oxyntomodulin analogue, in a 10 mg vial
Mazdutide, also known by the codes IBI362 and LY3305677, is a synthetic analogue of oxyntomodulin, a gut hormone that activates both the GLP-1 receptor and the glucagon receptor. This listing is a single 10 mg vial of white freeze-dried powder. Research on mazdutide concerns that dual receptor activity and how it was studied in phase 1b and phase 2 trials in Chinese adults with overweight or obesity, followed by a phase 3 programme also run in China.
Specifications
| Property | Value |
|---|---|
| Compound | Mazdutide IBI362; LY3305677; acylated oxyntomodulin analogue (GLP-1/glucagon dual agonist) |
| CAS number | 2259884-03-0 |
| Molecular formula | C210H322N46O67 |
| Theoretical mass | 4563.1 Da |
| Sequence / structure | H-H-Aib-QGTFTSDYSKYLDEKKAK(γGlu-2×AEEA-C20 diacid)EFVEWLLEGGPSSG-NH₂ (34 residues; Aib2; Lys20 acylated with eicosanedioic acid via γ-Glu and two AEEA spacers; C-terminal amide) |
| Label claim | 10 mg/vial |
| Form | Lyophilized (freeze-dried) powder or cake in a sealed glass vial with a rubber stopper and aluminium crimp cap |
| Storage, sealed | −20 °C, desiccated, dark |
| Purity specification | 99.0% or higher by RP-HPLC |
| Lot certificate | Results for the lot now shipping are in the certificate panel on this page |
| Safety data sheet | PL-SDS-106 |
Structure and molar amount
The lot certificate gives mazdutide as a 34-residue peptide with an amidated C-terminus. Position 2 is α-aminoisobutyric acid (Aib), and lysine 20 carries a 20-carbon diacid (eicosanedioic acid) joined through a γ-glutamate and two AEEA spacers. The formula is C210H322N46O67 and the theoretical mass 4563.1 Da, the figure the LC-MS identity result on the certificate is compared against. The parent hormone is a little longer: the site’s guide describes oxyntomodulin as a 37-residue product of the proglucagon gene that contains the full 29-residue glucagon sequence plus an eight-residue extension.
At 4563.1 Da, 10 mg of mazdutide is about 2.2 µmol. Residual water in the powder, reported on the certificate, brings the true peptide content slightly below that. The peptide purity testing article explains what the purity and identity figures on a certificate mean.
Handling and stability
The safety data sheet classifies mazdutide as Repr. 2 (H361), the GHS category for substances suspected of damaging fertility or the unborn child, and asks for the vial to be stored locked up. Sealed vials go to −20 °C, desiccated and dark, and should reach room temperature before opening so that condensation does not form on the powder. Reconstituted solutions are kept at 2 to 8 °C away from light and used within a period your laboratory has set.
No paper cited here reports how stable mazdutide is in solution. The general background is in a review of protein pharmaceuticals by Manning and colleagues, which covers chemical and physical instability and has separate sections on stabilisation in aqueous solution and in the dried state1. Peptide storage and stability applies the same principles to research peptides.
What the research covers
Oxyntomodulin and the dual receptor idea
Oxyntomodulin is released from the gut after meals and activates both the GLP-1 receptor and the glucagon receptor2. In a 2014 review, Pocai credited this dual activity with greater body weight lowering than selective GLP-1 receptor agonists, and summarised human studies in which oxyntomodulin reduced food intake and increased energy expenditure2. The glucagon side carries a known risk, because glucagon receptor activation increases glucose production. Pocai noted that simultaneous GLP-1 receptor activation counteracts this, and that an acute oxyntomodulin infusion improved glucose tolerance in people with type 2 diabetes2. On that basis the review presented dual agonists of the two receptors as promising new drug candidates for diabetes and obesity2. Mazdutide keeps the two receptor targets of the parent hormone but adds the Aib substitution and fatty acid side chain listed on the certificate, changes the site’s guide describes as helping the peptide survive in the blood and ride on albumin.
Phase 1b in Chinese adults
The phase 1b study, published in 2021, was randomised, placebo-controlled and masked, and enrolled Chinese adults at six centres who had overweight (a BMI of 24 or more with hyperphagia or at least one comorbidity) or obesity (a BMI of 28 or more)3. Participants were assigned 2:1 to IBI362 or placebo in each of three cohorts for 12 weeks, with eight further weeks of safety follow-up; the trial is registered as NCT044403453. Safety and tolerability were the primary end points, and the study also assessed pharmacokinetics and efficacy3.
Phase 2
A randomised, double-blind, placebo-controlled phase 2 trial at 20 hospitals in China assigned 248 adults with overweight or obesity to one of three mazdutide groups or placebo, with the percentage change in body weight at week 24 as the primary endpoint4. The published 24-week results were an interim analysis of a two-part trial4. Mean body weight changed by −6.7%, −10.4% and −11.3% in the three mazdutide groups and by +1.0% with placebo, and the most common adverse events were diarrhoea, nausea and upper respiratory tract infection4. The authors described all three mazdutide groups as well tolerated4.
Later trials and what is not established
The phase 3 trials, GLORY-1 and GLORY-2 in obesity and two DREAMS trials in type 2 diabetes, are summarised in the mazdutide vs survodutide vs tirzepatide guide, which also records that China’s drug regulator approved mazdutide in June 2025. It has no FDA approval. Every trial described here enrolled Chinese adults, so how the findings carry over to other populations is an open question, and no head-to-head trial against survodutide, tirzepatide or retatrutide has been published. The abstracts cited here do not report mazdutide’s relative potency at the two receptors. All of the human work used the clinical drug product under medical supervision; none of it involved research-grade material.
How each lot is tested
Every lot is tested in PrymaLab’s own laboratory in Ashland, Kentucky before release: RP-HPLC for purity, LC-MS for identity, Karl Fischer titration for water, LAL for endotoxin and USP <71> for sterility. The results for the lot now shipping are in the certificate panel on this page, and the certificate number, key and QR code can be checked on the verify page. These are in-house results from PrymaLab Analytical, not an independent test, and the lab is not accredited to ISO 17025. The third-party testing guarantee on this page still applies: if any independent laboratory finds the wrong compound, or less than the stated purity or amount, the order is refunded and the cost of the test is reimbursed.
Frequently asked questions
How does mazdutide compare with survodutide and retatrutide?
All three are lipidated peptides with glucagon receptor activity. Mazdutide and survodutide act at two receptors, GLP-1 and glucagon; mazdutide is built on oxyntomodulin and survodutide on glucagon. Retatrutide adds the GIP receptor for a total of three. No trial has compared them directly.
What does the certificate for this vial show?
The certificate panel on this page gives the results for the lot now shipping, with the lot number to match against the vial label. The identity result should agree with the 4563.1 Da theoretical mass, and any certificate can be checked by number and key on the verify page.
How should mazdutide be stored?
Sealed at −20 °C, dry and dark, and brought to room temperature before opening. After reconstitution keep the solution at 2 to 8 °C, protected from light, and use it within the period your lab has validated. The safety data sheet also asks for the vial to be stored locked up.
Is mazdutide approved?
Only in China, where the regulator approved it in June 2025. It is not approved by the FDA. This vial is not that medicine: it is a research compound sold for laboratory use only and must not be given to people or animals.
What does the published research leave open?
The phase 1b, phase 2 and phase 3 trials were all run in Chinese adults, the balance of potency between the two receptors is not reported in the abstracts cited here, and no head-to-head comparison with other dual or triple agonists has been published.
References
- Manning MC, Chou DK, Murphy BM, et al. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544-75. DOI · PubMed
- Pocai A. Action and therapeutic potential of oxyntomodulin. Mol Metab. 2014;3(3):241-51. DOI · PubMed
- Ji L, Jiang H, An P, et al. IBI362 (LY3305677), a weekly-dose GLP-1 and glucagon receptor dual agonist, in Chinese adults with overweight or obesity: A randomised, placebo-controlled, multiple ascending dose phase 1b study. EClinicalMedicine. 2021;39:101088. DOI · PubMed
- Ji L, Jiang H, Cheng Z, et al. A phase 2 randomised controlled trial of mazdutide in Chinese overweight adults or adults with obesity. Nat Commun. 2023;14(1):8289. DOI · PubMed
Research use only
For laboratory research use only. Mazdutide 10mg is not a drug, food, cosmetic or dietary supplement, is not approved by the FDA or any comparable authority for human or veterinary use, and must not be given to people or animals. It is sold to qualified researchers and institutions, and the buyer is responsible for lawful handling and disposal.
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