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Research profile · Peptide analogue

Mazdutide

Also known as IBI362, LY3305677

Clinical — evidence level 4 of 4: Established clinical evidenceExperimental — UK regulatory status: Experimental — not authorised for human use in the UK

Overview

A dual glucagon and GLP-1 receptor agonist with four published phase 3 trials, all conducted in China.

Category
Peptide analogue
Highest evidence level identified
Established clinical evidence
Last scientifically reviewed
20 August 2026
Last regulatory review
20 August 2026

Mechanism under investigation

Mazdutide is a synthetic once-weekly analogue of mammalian oxyntomodulin that acts at two receptors: the glucagon receptor and the glucagon-like peptide-1 receptor. Activation of the GLP-1 receptor drives glucose-dependent insulin secretion and reduced appetite. The added glucagon-receptor component is proposed to raise energy expenditure and affect hepatic fat metabolism, which distinguishes it from single-target GLP-1 analogues. It is developed by Innovent Biologics with Eli Lilly.

Research areas

  • Metabolic research
  • Incretin biology

These are fields in which the compound has been investigated. Listing a field is not a statement that anything was demonstrated within it.

Current evidence

In-vitro evidence

Cells, tissues or biochemical systems outside a living organism.

Thinly represented. No primary in-vitro pharmacology paper for mazdutide itself is indexed; receptor characterisation appears inside reviews and clinical papers rather than as standalone published work.

Animal evidence

Studies in living non-human animals.

No primary preclinical animal study of mazdutide is indexed in the literature databases searched. This is unusual for a compound at this stage of development and limits independent mechanistic scrutiny.

Human observational evidence

Studies observing people without assigning an intervention.

Absent. No cohort or registry data — the compound is recent and its authorised use is confined to one market.

Clinical-trial evidence

Studies assigning an intervention to human participants.

Substantial, and by a distance the strongest tier. Four phase 3 trials are published. In a 48-week obesity trial of 610 adults, body weight changed by −11.0 and −14.0 per cent in the two treatment arms against +0.3 per cent for placebo. A 60-week trial of 461 adults reported −16.7 per cent against −1.5 per cent for placebo. Two type 2 diabetes trials followed: one against placebo in 320 adults, and one against dulaglutide in 731 adults, where mazdutide was both non-inferior and superior on glycated haemoglobin. Across all four the most common adverse events were gastrointestinal.

Study limitations

  • Every phase 3 trial to date enrolled exclusively Chinese adults. Generalisability to UK populations is untested, and this matters given the different body-mass-index thresholds used for entry.
  • Trial durations are short relative to the chronic conditions studied, at 24 to 60 weeks. There are no cardiovascular outcome data, no mortality data and no long-term safety data.
  • Adding glucagon-receptor activation to GLP-1 activation is mechanistically novel, so the long-term consequences of sustained glucagon-receptor agonism on hepatic glucose output, heart rate and blood pressure are not characterised by any long-duration study.
  • The only active comparator studied is dulaglutide. Head-to-head phase 3 data against semaglutide and tirzepatide — the relevant UK comparators — were still in progress at the time of review.
  • Almost all trials are sponsored by the developers, and no independent replication outside that programme is published.
  • The preclinical record is unusually thin: no primary in-vitro or animal pharmacology paper for mazdutide was retrievable.

UK regulatory context

Experimental — not authorised for human use in the UK

A compound appearing in research literature that holds no UK authorisation for human use in any indication.

Source: The Human Medicines Regulations 2012, regulation 46 — prohibition on sale or supply of an unauthorised medicinal product (opens legislation.gov.uk in a new tab) (legislation.gov.uk)

Regulatory classification is jurisdiction-specific. A compound authorised elsewhere is not thereby authorised in the UK, and a supplier’s description of a substance does not determine how it is classified in law. See safety and regulation for the framework and the authoritative sources.

Safety and interpretation

The published safety signal is dominated by gastrointestinal adverse events, and in the highest-dose phase 3 trial these were reported at rates well above placebo — vomiting in 53.1 per cent against 1.3 per cent, nausea in 46.9 per cent against 3.2 per cent, and diarrhoea in 39.4 per cent against 6.5 per cent. That pattern is consistent with the GLP-1 receptor agonist class, but the absolute rates warrant plain statement rather than a general assurance of tolerability. Beyond that the picture is incomplete: no long-term follow-up, no cardiovascular outcome trial, no data in UK or European populations, and no assessment of benefit and risk by any UK or European regulator.

References