What Is Mazdutide? Oxyntomodulin-Based Dual Agonist: Structure, Mechanism and Research

Mazdutide (development codes IBI362 and LY3305677) is a lipidated peptide built on the oxyntomodulin template that activates both the GLP-1 receptor and the glucagon receptor. What distinguishes it from the other glucagon-containing duals is where it came from. Oxyntomodulin, a peptide cut from proglucagon, already stimulates both receptors in the body, so mazdutide is an improved version of a naturally occurring dual agonist — not a single-receptor drug that was later given a second activity. We supply research-grade mazdutide freeze-dried in sealed vials, for laboratory use only.

Mazdutide remained an investigational compound without marketing authorisation as of 2026. The research-grade product is a reference chemical, and this page contains no protocol for use in people.

Mazdutide defined

Proglucagon is processed differently in different tissues. In pancreatic alpha cells the main product is glucagon; in the L-cells of the gut it yields GLP-1, GLP-2 and oxyntomodulin. Oxyntomodulin consists of the glucagon sequence followed by eight further C-terminal residues, and that tail changes its receptor preferences so that it activates GLP-1R as well as the glucagon receptor — weakly, and only for the few minutes before it is broken down, but at both. Dual receptor agonism is thus something human physiology already does, and mazdutide is an attempt to make that activity strong and durable enough to investigate.

The molecule relies on the standard toolkit for this class: amino-acid changes that protect it from DPP-4, and a fatty side chain for reversible albumin binding. It is registered as CAS 2259884-42-1 and also appears as IBI362 and LY3305677. Our specification sheet does not list a molecular weight; if you need an exact mass to calculate molarity, take it from the certificate for your lot.

Design and structure

• Template. Oxyntomodulin: the glucagon sequence plus the C-terminal tail that gives it affinity for GLP-1R.
• Protease resistance. Modifications near the N-terminus block DPP-4, the enzyme that limits every natural proglucagon peptide to a working life of minutes.
• Fatty-acid chain. Attached through a spacer, it promotes binding to albumin; published pharmacokinetic data put the resulting circulation time at several days.
• Split between receptors. In published characterisation, activity leans toward GLP-1R while retaining a smaller glucagon receptor component that still matters pharmacologically.

Mechanism of action

Although both receptors are class B GPCRs that raise cAMP through Gs, they sit in different tissues and produce different physiology. GLP-1R activation in islet preparations increases insulin secretion when glucose is high, and receptors in the hypothalamus, hindbrain and vagus are believed to account for the reduced feeding and slower gastric transit seen in rodents. The glucagon receptor acts mainly in the liver: studies there describe more fatty-acid oxidation and altered handling of hepatic lipid, with whole-body energy expenditure rising in preclinical models.

The rationale for combining the two receptors is that each arm cancels the other's drawbacks and adds to its strengths. Glucose-dependent insulin release driven by the incretin arm offsets the extra glucose the liver would otherwise produce under glucagon receptor stimulation, while the glucagon arm's effect on energy expenditure is kept. Because oxyntomodulin-derived compounds inherit a receptor balance selected by evolution rather than chosen by chemists, researchers frequently use them as a physiological reference point when evaluating engineered dual agonists.

Research applications

• Cell and receptor studies. Binding and cAMP potency measurements on human GCGR and GLP-1R in transfected cell systems to establish the activity ratio, plus bias work such as arrestin recruitment.
• Animal studies. Feeding and body composition in diet-induced obese rodents, indirect calorimetry to separate out the energy-expenditure contribution of glucagon receptor signalling, and liver-fat measurements in fatty-liver models.
• Human trials. Phase 2 and phase 3 findings have been published, with a large share of the programme conducted in Chinese populations — worth noting for cross-class comparisons, since trial populations and baseline metabolic characteristics are not interchangeable. These studies examined an investigational medicine under clinical supervision and say nothing about research-grade powder.

For where mazdutide sits in the wider landscape, see our overview of next-generation GLP-1 molecules and the incretin signalling hub.

One design warning holds for every dual agonist that includes glucagon activity. The glucagon receptor's pharmacology differs more from species to species than GLP-1R's does, so a potency ratio obtained on rodent receptors may not apply to the human receptors. If a paper attributes an effect to the glucagon component, that claim is far more credible when a glucagon receptor antagonist arm or a GLP-1-only comparator such as semaglutide is included. Without such a control, the effect cannot be distinguished from a simply stronger incretin response at higher occupancy.

When selecting between glucagon-containing duals, the variable that actually matters is the ratio between the two receptor activities, not the product name. Two compounds that both engage both receptors can behave very differently if one is weighted ten times more heavily toward GLP-1R. And the ratio depends on how it is measured — cAMP potency in a recombinant over-expressing cell line need not match what primary hepatocytes with native receptor density show. If the balance between arms is central to your study, measure it in your own system rather than importing a number from someone else's. If what you need is simply a dual-agonist reference with a physiological pedigree, mazdutide is a reasonable default, as its balance comes from oxyntomodulin rather than from a design target.

Available formats and vial sizes

Available vial sizes and current prices are listed on the mazdutide product page, which sits in the GLP-1 and incretin peptides collection.

Reconstitution and storage at the bench

The following is arithmetic, not a usage instruction: adding 4 mL of bacteriostatic water to a 20 mg vial gives 5 mg/mL (5,000 mcg/mL), and 0.2 mL of that solution holds 1,000 mcg of peptide. Where an assay requires a specific buffer, weak alkaline or phosphate buffers are usual for this class — confirm beforehand that they are compatible with your detection method.

Let the diluent run gently down the vial wall, swirl rather than shake, and check that the solution is completely clear before using it. Unopened freeze-dried vials go at −20 °C, dry and dark; reconstituted solution is kept at 2–8 °C, away from light, and used within the study window. Split the solution into aliquots as soon as it is made, so the stock is not damaged by repeated freeze-thaw cycles. The reconstitution guide has more detail.

Purity and reading the certificate of analysis

For mazdutide, the certificate should contain an HPLC chromatogram with the main peak's area percentage, a mass-spec identity result, the net peptide content, lot number and analysis date. Confirming identity is especially important here, for two reasons: the glucagon-containing duals resemble each other structurally, and mazdutide is published under three different names, which makes matching a supplier's product to a literature characterisation harder than it ought to be. Since our specification sheet omits the molecular weight, use the lot certificate for any molar calculation. See how to read a COA.

From a purchasing point of view, the crucial fact is that compounds in this class cannot be swapped for one another. Two glucagon-containing duals of identical nominal purity can produce different results in the same assay simply because their receptor balances differ — and neither result is an error. Recording exactly which compound, lot and certificate underlie a data set is therefore part of the science, not administration, and it is the only way another lab following the same published description can reproduce the work.

Regulatory position

As of 2026, mazdutide has no marketing approval in the United States, where it remains investigational. Because its trials have been concentrated in particular regions, its regulatory standing differs between jurisdictions — but a filing or approval in one market does not change the status of research-grade material anywhere. We supply mazdutide as a laboratory reference chemical, for research use only and not for human consumption.

Related compounds and comparisons

Structurally, the nearest comparator is survodutide — the other glucagon-containing dual agonist we stock — and the two are compared in survodutide vs mazdutide. Retatrutide adds GIP to the same pair of receptors, making it a triple agonist; tirzepatide is the dual that pairs GLP-1 with GIP instead.

Matching catalogue section: GLP-1 & Incretin Peptides