What Is Efinopegdutide? Definition and What Research Reports

Definition

Efinopegdutide is an investigational, long-acting synthetic peptide designed to activate two receptors at the same time: the glucagon-like peptide-1 (GLP-1) receptor and the glucagon receptor. In the published literature it is usually described as a dual GLP-1/glucagon receptor agonist or co-agonist, and it has been evaluated by subcutaneous injection in metabolic research settings, including a phase IIa study in patients with non-alcoholic fatty liver disease that dosed it once weekly alongside an active comparator (phase IIa trial). It is not an approved medicine in the United States; it appears in the literature as a clinical-stage investigational compound. This page is for educational purposes only and is not medical advice; consult a licensed physician about any medical or treatment question.

What Class of Molecule It Is

Efinopegdutide belongs to the incretin-based peptide family — engineered analogues of gut and pancreatic hormones that bind hormone receptors involved in glucose handling, appetite signalling and energy expenditure. Where a single-agonist molecule engages only the GLP-1 receptor, efinopegdutide is built as a balanced or dual agonist, combining GLP-1 receptor activity with glucagon receptor activity in one peptide backbone. Narrative reviews tracing this field have described the progression from GLP-1 monotherapy to dual and triple receptor agonists as a distinct phase in metabolic drug development, with GLP-1/glucagon co-agonists among the designs examined (review of incretin-based therapies).

The rationale described in that literature is mechanistic: GLP-1 receptor activity is associated with reduced food intake and improved glycaemic parameters, while glucagon receptor activity is discussed in relation to hepatic energy metabolism and energy expenditure. Combining the two in a single molecule is the design premise, and reviews of emerging GLP-1 receptor agonists for obesity have catalogued efinopegdutide among the co-agonist candidates that entered clinical evaluation (review of emerging GLP-1 receptor agonists).

Where the Name Comes From

The -glutide ending in the generic name places efinopegdutide in the same naming family as other glucagon-family peptide analogues such as liraglutide, semaglutide and dulaglutide. The -peg- element in the middle of the name reflects the use of polyethylene glycol conjugation, a common half-life-extension strategy for peptides. Not every metabolic peptide shares this stem: tirzepatide, for example, is a GIP/GLP-1 receptor co-agonist and carries a different naming stem, so the ending alone should not be read as a complete description of a molecule's receptor targets.

How the Term Is Used in Peptide Research

In research writing, "efinopegdutide" is used in three recurring ways:

• As a named investigational compound in clinical trial reports, where the study design, weekly subcutaneous dosing and comparator arm are described.
• As a class exemplar — a concrete example of the GLP-1/glucagon dual agonist concept when reviews contrast single-, dual- and triple-agonist designs (incretin evolution review).
• As a comparator node in systematic reviews and network meta-analyses that pool multiple metabolic agents and rank them on outcomes such as liver fat content or body weight (network meta-analysis of MASH therapies).

Because the compound is investigational, the literature around it is concentrated in trial reports and evidence syntheses rather than in long-term outcome data or post-marketing surveillance.

Quick Reference

What the Published Literature Reports

Liver fat

The most cited primary study is a phase IIa, active-comparator-controlled trial in patients with non-alcoholic fatty liver disease, in which researchers compared once-weekly subcutaneous efinopegdutide with an active GLP-1 receptor agonist comparator over 24 weeks and reported a significantly greater relative reduction in liver fat content, measured by MRI-based proton density fat fraction, in the efinopegdutide arm (Journal of Hepatology, 2023). A later network meta-analysis that pooled pharmacologic therapies for metabolic dysfunction-associated steatohepatitis included efinopegdutide among the compared agents and reported relative rankings for reduction in liver fat content across the treatment network (Hepatology network meta-analysis). A separate systematic review and meta-analysis of GLP-1-based therapies in MASLD and MASH summarised effects across this drug class on hepatic and metabolic endpoints (JCEM, 2025).

Body weight

Efinopegdutide has also appeared as a comparator in weight-focused evidence syntheses: a systematic review and meta-analysis compared semaglutide against liraglutide or efinopegdutide in patients with obesity and reported pooled weight-loss outcomes across those comparisons (Cureus, 2024). Earlier narrative work on emerging GLP-1 receptor agonists for obesity had already positioned dual GLP-1/glucagon agonists, efinopegdutide among them, as candidates under clinical investigation for weight-related endpoints (Expert Opinion on Emerging Drugs, 2021).

Adverse Events: What Studies Report

In the phase IIa fatty liver disease study, the investigators reported that gastrointestinal adverse events — the class-typical complaints associated with GLP-1 receptor activation, such as nausea, vomiting and diarrhoea — were the most frequently observed events in participants receiving efinopegdutide (phase IIa safety reporting). Broader syntheses of GLP-1-based therapies in steatotic liver disease have similarly summarised tolerability alongside efficacy for this therapeutic class (systematic review and meta-analysis). Because the published dataset is limited to relatively short trials and pooled analyses, long-term safety characterisation for this specific molecule is not established in the cited literature.

What the Literature Does Not Establish

The cited papers describe short-duration, surrogate-endpoint research: imaging-measured liver fat, metabolic markers and body weight. They do not report long-term histological outcomes, cardiovascular outcome data, or comparative effectiveness against the full range of newer dual and triple agonists. Reviews of the incretin field have noted that the shift toward multi-receptor agonists is recent and that the comparative evidence base is still developing (incretin evolution review). Nothing on this page describes how any compound should be used; it summarises what published studies reported.

References

• A phase IIa active-comparator-controlled study to evaluate the efficacy and safety of efinopegdutide in patients with non-alcoholic fatty liver disease (Journal of Hepatology, 2023)
• Emerging glucagon-like peptide 1 receptor agonists for the treatment of obesity (Expert Opinion on Emerging Drugs, 2021)
• Efficacy of GLP-1-based Therapies on Metabolic Dysfunction-associated Steatotic Liver Disease and Metabolic Dysfunction-associated Steatohepatitis: A Systematic Review and Meta-analysis (The Journal of Clinical Endocrinology and Metabolism, 2025)
• Comparative Efficacy of Semaglutide Versus Liraglutide or Efinopegdutide on Weight Loss in Obese Patients: A Systematic Review and Meta-Analysis (Cureus, 2024)
• Comparative efficacy of pharmacologic therapies for MASH in reducing liver fat content: Systematic review and network meta-analysis (Hepatology, 2026)
• Evolution of incretin-based therapies: From GLP-1 monotherapy to dual and triple agonists: A new era in metabolic therapy (The Indian Journal of Medical Research, 2026)