Reference guide

GLP-1, GIP and Triple Agonists Explained

This is a reference page explaining how the three receptor classes differ — it is not a buying page. If you already know which compound you need, the dedicated pages are linked in each section below.

Every analogue in this class works by mimicking incretin hormones. What separates them is how many receptor families a single molecule activates: one, two or three.

Single agonist — GLP-1 only

Semaglutide activates the GLP-1 receptor alone and carries the longest published research record of the three, which is why it is usually the reference compound in comparative studies. Full strengths, pricing and handling notes are on the Semaglutide vials page.

Dual agonist — GLP-1 and GIP

Tirzepatide adds GIP receptor agonism alongside GLP-1 in one molecule, sitting between the single and triple classes in the research landscape. Strengths and reconstitution volumes are covered on the Tirzepatide vials page.

Triple agonist — GLP-1, GIP and glucagon

Retatrutide is the newest class, adding glucagon receptor agonism on top of GLP-1 and GIP. It is the most active area of current metabolic peptide research. Strength options, cost per mg and reconstitution guidance are on the Retatrutide vials page, and the science background is covered in what is Retatrutide.

Choosing between the classes

Direct side-by-side breakdowns live on Retatrutide vs Semaglutide and Retatrutide vs Tirzepatide, which compare receptor targets, typical research protocols and cost per mg.

Reconstitution and storage — common to all three

Every compound in this class ships lyophilised. Reconstitute with bacteriostatic water, store the reconstituted solution at 2–8°C. Add water slowly down the inside wall of the vial and swirl — never shake. The reconstitution calculator works out volumes and units for any strength.

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Frequently asked questions

What are GLP-1 research peptides?

GLP-1 (glucagon-like peptide-1) research peptides are synthetic analogues of the natural GLP-1 hormone, including Semaglutide, Tirzepatide and Retatrutide. They are studied for their effects on glucose regulation and metabolism in laboratory settings.

What is the difference between a single, dual and triple agonist?

A single agonist such as Semaglutide activates the GLP-1 receptor only. A dual agonist such as Tirzepatide activates GLP-1 and GIP receptors. A triple agonist such as Retatrutide activates GLP-1, GIP and glucagon receptors. Each added receptor target changes the metabolic profile studied in the literature.

Which GLP-1 analogue has the longest research history?

Semaglutide has the longest published research history, Tirzepatide has extensive dual-agonist metabolic data, and Retatrutide is the newest of the three with research focused on its triple-receptor profile.

Do all three classes reconstitute the same way?

Broadly yes. All ship lyophilised and are reconstituted with bacteriostatic water, then stored at 2-8C and used within the standard refrigerated window. The volume differs by vial strength, which is what the reconstitution calculator works out.

Are GLP-1 research peptides a licensed medicine?

No. Every compound in this class is supplied for laboratory research only. For In Vitro Use Only - Not for Human Use.

Disclaimer: All products sold by Peptides UK 4U are for laboratory and research purposes only. They are not intended for human or animal consumption, diagnosis, treatment or prevention of any disease.