What Is Mazdutide? Definition and What Research Reports

Plain-language definition

Mazdutide is the international non-proprietary name for a laboratory-made peptide that is given as a once-weekly injection and that switches on two different receptors in the body at the same time — the receptor for GLP-1 (a gut hormone involved in appetite and insulin release) and the receptor for glucagon (a pancreatic hormone involved in glucose output and energy expenditure). Because it acts at two targets rather than one, it is usually described as a dual agonist. It was investigated mainly in Chinese adults with obesity, overweight or type 2 diabetes, and a 2025 review in Drugs documented its first regulatory approval (PMID 41028652).

The term in biochemical and regulatory language

In technical writing, mazdutide is defined as a GLP-1 receptor (GLP-1R) and glucagon receptor (GCGR) dual agonist peptide. That phrasing is used directly in the title of a 2025 EBioMedicine paper describing mechanistic work on mazdutide (PMID 40479843). The molecule appeared in earlier literature under development codes rather than its current name: a 2022 phase 1b trial in Chinese patients with type 2 diabetes was published under the identifiers IBI362 and LY3305677 (PMID 35750681), and a separate 2022 multiple-ascending-dose phase 1b trial in adults with overweight or obesity used the label "IBI362" alongside the newer name (PMID 36247927).

Regulatory status is part of the definition for anyone reading trial literature. The Drugs "First Approval" article summarised mazdutide's transition from investigational agent to approved medicine (PMID 41028652). Approval status is country-specific and changes over time; the published record, not marketing material, is the reference point. This page is for educational purposes only and is not medical advice; consult a licensed physician about any medical question.

Names and labels used for the same molecule

How the term is used in peptide research

In the research literature, "mazdutide" is used narrowly: it names a specific investigational-then-approved peptide with a defined clinical trial programme. Papers generally fall into four groups — early-phase pharmacology and dose-ranging studies, phase 2 randomised trials, phase 3 trials with placebo or active comparators, and preclinical mechanistic work. A 2024 systematic review and meta-analysis of randomised controlled trials pooled weight outcomes across diabetic and non-diabetic participants, which is the usual sign that a compound has accumulated enough trials for synthesis (PMID 38440786).

Where the term is misused

• As a generic label for "dual agonist". Mazdutide is one specific GLP-1R/GCGR molecule; it is not interchangeable with other multi-receptor peptides that hit different receptor combinations.
• As shorthand for "the same as tirzepatide or semaglutide". Those compounds engage different receptor sets, and cross-compound claims cannot be read off mazdutide trials.
• As a "research-only chemical". Material sold under research-use-only labelling is not the same as the manufactured product studied in the registration trials described in the Drugs review (PMID 41028652); identity, purity and formulation are not established by a name on a vial.
• As a term carrying results from one population to all populations. The large published trials enrolled Chinese adults (PMID 40421736, PMID 41407859), a detail routinely dropped in secondary summaries.

What the published literature reports

Early-phase studies

A randomised, placebo-controlled multiple-ascending-dose phase 1b trial examined mazdutide (IBI362) at 9 mg and 10 mg in Chinese adults with overweight or obesity, and researchers reported on safety and efficacy at those dose levels (PMID 36247927). A companion phase 1b trial evaluated the same molecule under the IBI362/LY3305677 codes in Chinese patients with type 2 diabetes (PMID 35750681). A later high-dose phase 1 trial published in 2025 reported that mazdutide reduced body weight in adults with overweight or obesity (PMID 40832785).

Phase 2 trials

A phase 2 randomised controlled trial in Chinese overweight adults or adults with obesity was published in Nature Communications in 2023; the study assessed body-weight outcomes against placebo (PMID 38092790). In type 2 diabetes, a randomised, double-blind, placebo-controlled phase 2 trial in Diabetes Care evaluated efficacy and safety in Chinese patients, with glycaemic control as the focus (PMID 37943529).

Phase 3 and comparator trials

A 2025 New England Journal of Medicine report described once-weekly mazdutide in Chinese adults with obesity or overweight, where researchers compared active doses with placebo over the trial period and reported greater reductions in body weight with mazdutide (PMID 40421736). Two 2026 Nature papers extended the diabetes programme: one compared mazdutide with placebo in Chinese adults with type 2 diabetes (PMID 41407859) and one compared it with dulaglutide, an established GLP-1 receptor agonist, in the same population (PMID 41407860). Pooled analysis across randomised trials in the 2024 meta-analysis reported weight reduction with mazdutide relative to comparators in both diabetic and non-diabetic participants (PMID 38440786).

Preclinical and mechanistic work

Beyond weight and glucose endpoints, a 2025 EBioMedicine study used multi-omics analysis to examine whether the GLP-1R/GCGR dual agonist mitigated diabetes-associated cognitive dysfunction, and the authors framed the work as mechanistic rather than clinical (PMID 40479843). Mechanistic findings of this kind describe biology in a model system and are not evidence of a clinical benefit in people.

Case-level reports

A 2025 case report in Frontiers in Endocrinology described dose-escalated mazdutide in a single adolescent with obesity, type 2 diabetes and hyperuricemia (PMID 41030857). A case report describes one individual under clinical supervision and cannot establish efficacy or safety for any group.

Adverse Events: What Studies Report

Across the mazdutide programme, tolerability was reported as a co-primary concern alongside efficacy. The phase 1b multiple-ascending-dose trial was explicitly framed around safety and efficacy at 9 mg and 10 mg (PMID 36247927), and the phase 2 diabetes trial in Diabetes Care reported safety outcomes alongside glycaemic results (PMID 37943529). Trials of incretin-based agents, including the once-weekly mazdutide trial reported in 2025, described gastrointestinal events — such as nausea, vomiting, diarrhoea and reduced appetite — as the most common treatment-emergent adverse events, generally mild to moderate and most frequent during dose escalation (PMID 40421736). The 2024 meta-analysis pooled adverse-event data across randomised trials in addition to weight outcomes (PMID 38440786). Full adverse-event tables, discontinuation rates and serious-event counts sit in the individual publications and the regulatory summary (PMID 41028652).

Related terms

• GLP-1 receptor agonist — a compound acting at the GLP-1 receptor only; mazdutide adds a second target (PMID 40479843).
• Glucagon receptor (GCGR) — the second receptor engaged by mazdutide.
• Dual agonist / multi-agonist — class terms for peptides designed to activate more than one receptor.
• Dulaglutide — the active comparator in the 2026 Nature head-to-head trial (PMID 41407860).
• Dose escalation — the stepwise design feature used in the high-dose phase 1 trial (PMID 40832785).

How to read mazdutide claims critically

1. Check the population: most published trials enrolled Chinese adults (PMID 41407859).
2. Check the phase: phase 1b dose-finding answers different questions than a phase 3 comparator trial (PMID 35750681, PMID 41407860).
3. Check whether a claim comes from a human trial or a mechanistic model (PMID 40479843).
4. Check whether the source is a single case (PMID 41030857) or a pooled analysis (PMID 38440786).

References

• Once-Weekly Mazdutide in Chinese Adults with Obesity or Overweight (The New England Journal of Medicine, 2025)
• Mazdutide: First Approval (Drugs, 2025)
• Mazdutide, a dual agonist targeting GLP-1R and GCGR, mitigates diabetes-associated cognitive dysfunction: mechanistic insights from multi-omics analysis (EBioMedicine, 2025)
• Efficacy and Safety of Mazdutide in Chinese Patients With Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled Phase 2 Trial (Diabetes Care, 2024)
• Mazdutide versus dulaglutide in Chinese adults with type 2 diabetes (Nature, 2026)
• A phase 2 randomised controlled trial of mazdutide in Chinese overweight adults or adults with obesity (Nature Communications, 2023)
• Mazdutide versus placebo in Chinese adults with type 2 diabetes (Nature, 2026)
• Safety and efficacy of a GLP-1 and glucagon receptor dual agonist mazdutide (IBI362) 9 mg and 10 mg in Chinese adults with overweight or obesity: a randomised, placebo-controlled, multiple-ascending-dose phase 1b trial (EClinicalMedicine, 2022)
• Efficacy and safety of Mazdutide on weight loss among diabetic and non-diabetic patients: a systematic review and meta-analysis of randomized controlled trials (Frontiers in Endocrinology, 2024)
• Mazdutide reduces body weight in adults with overweight or obesity: A high-dose Phase 1 trial (Diabetes, Obesity & Metabolism, 2025)
• A phase 1b randomised controlled trial of a glucagon-like peptide-1 and glucagon receptor dual agonist IBI362 (LY3305677) in Chinese patients with type 2 diabetes (Nature Communications, 2022)
• Case Report: Efficacy and safety of dose-escalated Mazdutide, a GLP-1/GCGR dual agonist, in an adolescent with obesity, type 2 diabetes, and hyperuricemia (Frontiers in Endocrinology, 2025)