GLP-1, GIP and glucagon: multi-agonist research peptides explained

BritishPeps research team · Updated 18 July 2026 · ~7 min read

Metabolic research is one of the most active areas in the peptide literature, and much of the recent attention is on compounds that act on more than one receptor at a time. This guide explains what the GLP-1, GIP and glucagon receptors are, and how single, dual and triple agonist reference compounds differ. It is informational only: the compounds described are supplied exclusively for in-vitro laboratory research and are not intended for human or veterinary use.

Three receptors, one theme

GLP-1, GIP and glucagon are signalling molecules involved in how the body manages energy. Their receptors sit in different tissues and influence overlapping pathways within metabolic models:

GLP-1 (glucagon-like peptide-1) — an incretin pathway heavily studied in glucose-handling research.
GIP (glucose-dependent insulinotropic polypeptide) — a second incretin pathway, usually studied alongside GLP-1.
Glucagon — a pathway associated with energy expenditure in research models.

The research question behind multi-agonists is easy to state: does acting on several of these pathways at once behave differently from acting on just one?

Single, dual and triple agonists

Reference compounds group according to how many of these receptors they activate:

Single agonist — acts on one receptor (a GLP-1-only compound, for instance). Used as the baseline in comparisons.
Dual agonist — Tirzepatide is a dual GIP/GLP-1 agonist, studied in glucose-metabolism and energy-balance models.
Triple agonist — Retatrutide (LY3437943) acts on the GIP, GLP-1 and glucagon receptors, and is frequently used to contrast multi-receptor signalling with single-receptor signalling.

In practice, researchers commonly line them up side by side — a single agonist as the reference, then a dual and a triple — to study how the model changes as each receptor is added.

Other metabolic reference compounds

Multi-agonists are not the only tools in metabolic research. Fragments and analogues are also studied for narrower questions: AOD-9604, a modified growth-hormone fragment studied in lipid-metabolism models; Tesamorelin, a stabilised GHRH analogue studied in visceral-fat metabolism research; and MOTS-C, a mitochondria-derived peptide studied in cellular-metabolism and exercise-response research. See the full metabolic research range for each written specification.

Reading the literature carefully

Two caveats are worth keeping in mind. First, most of this work is preclinical or in vitro, so the literature describes what is being investigated, not settled results. Second, compound identity and purity determine whether a study is reproducible — which is why every reference vial should carry a written specification and documented purity (here, ≥98% by HPLC on every batch).

Frequently asked questions

Are these compounds for human use?

No. Retatrutide, Tirzepatide and the other compounds discussed here are supplied exclusively for in-vitro laboratory research and are not intended for human or veterinary use.

What is the difference between Retatrutide and Tirzepatide in research?

Tirzepatide is a dual GIP/GLP-1 agonist; Retatrutide adds a third pathway (glucagon), making it a triple agonist. They are often compared to study how a metabolic model changes when that receptor is added.

What does "agonist" mean here?

An agonist is a molecule that activates a receptor. A multi-agonist activates more than one receptor type, which is precisely the property this research examines.

For research use only. This content is informational and describes laboratory research. The products mentioned are supplied exclusively for scientific and in-vitro laboratory research, not for human or veterinary use. You must be 18 or over to place an order.