Mazdutide UK — What It Is, How It Works & Research Status
Also known as LY-3305677 / IBI-362
Mazdutide (LY-3305677, also known as IBI-362) is an investigational peptide based on the oxyntomodulin scaffold. It is a dual agonist — it activates the GLP-1 receptor and the glucagon receptor together, a different pairing from the GLP-1 + GIP combination used by Tirzepatide.
This page covers the mechanism, what the published trial programme has reported, how Mazdutide sits alongside the other incretin peptides, and its legal and availability status in the UK in 2026.
For in vitro research use only — not for human or animal consumption. Not a licensed medicine in the UK. Nothing on this page is medical advice.
What is Mazdutide?
Mazdutide is a synthetic analogue of oxyntomodulin, a naturally occurring gut hormone that binds both GLP-1 and glucagon receptors. Where most incretin research compounds are engineered from GLP-1 itself, Mazdutide starts from a molecule that is already dual-acting and modifies it for stability and a longer half-life.
It was licensed by Innovent Biologics for development in China and has progressed through a substantial clinical programme there, which is why the published literature on it is growing quickly while Western regulatory approval remains outstanding.
How the GLP-1/glucagon mechanism differs
The two incretin pathways — GLP-1 and GIP — are associated in research with satiety signalling and glucose-dependent insulin release. Glucagon-receptor activation is associated with energy expenditure and hepatic lipid handling rather than appetite.
Mazdutide therefore pairs an intake pathway with an expenditure pathway, the same logic behind the glucagon arm of Retatrutide, but without the GIP component.
- Semaglutide — single agonist (GLP-1)
- Tirzepatide — dual agonist (GLP-1 + GIP)
- Mazdutide — dual agonist (GLP-1 + glucagon)
- Retatrutide — triple agonist (GLP-1 + GIP + glucagon)
What the published research reports
Published Phase 2 and Phase 3 data from the Chinese programme report dose-dependent metabolic endpoints alongside the gastrointestinal effects typical of the incretin class — nausea, reduced appetite and transient GI upset, most pronounced during dose escalation.
As with every compound in this class, the literature is clinical research data. It is summarised here for context only and is not medical advice, and Mazdutide is not for human use.
Handling and storage
Lyophilised vials are stable at ambient temperature in transit and should be refrigerated on arrival. Reconstitute with bacteriostatic water added slowly down the vial wall, swirl rather than shake, then store at 2–8°C and use within 28 days.
Buying this peptide in the UK
- UK-held stock — same working day dispatch on orders before 2pm, Mon–Fri.
- Royal Mail Tracked 24 with photo confirmation on every parcel.
- Independent HPLC and mass-spec testing with a batch-matched Certificate of Analysis.
- Discreet plain packaging and normal UK card checkout — no crypto required.
- Free 4 needles + 4 alcohol swabs with every vial — opt in at checkout.
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View full shopFrequently asked questions
Is Mazdutide the same as Retatrutide?
No. Mazdutide is a dual GLP-1/glucagon agonist built on the oxyntomodulin scaffold. Retatrutide is a triple agonist that adds GIP receptor activity on top of those two pathways.
Is Mazdutide legal in the UK?
Mazdutide is legal to buy and possess in the UK for laboratory research purposes. It is not a licensed medicine in the UK, is not prescribed by the NHS, and is supplied strictly for in vitro research use only — not for human or animal consumption.
How is Mazdutide reconstituted?
Mazdutide is supplied lyophilised. Add bacteriostatic water slowly down the inside wall of the vial and swirl gently — never shake, as agitation can damage the peptide chain. Once dissolved, store at 2–8°C and use within 28 days. Use our free peptide calculator for exact volumes rather than following generic charts.
Do you supply a Certificate of Analysis for Mazdutide?
Yes. Every batch is independently HPLC and mass-spec tested and the batch number on the vial matches a published Certificate of Analysis, so purity can be verified before use.
How fast is UK delivery?
Stock is held in the UK. Orders placed before 2pm Monday–Friday are dispatched the same working day by Royal Mail Tracked 24 with photo confirmation, in discreet plain packaging with no product names on the outside.
Disclaimer: All products sold by Peptides UK 4U are for laboratory and research purposes only. They are not intended for human or animal consumption, diagnosis, treatment or prevention of any disease.