What Is GLP-3? Triple Agonist Peptide Guide

“GLP-3” is a name that causes a lot of confusion in the metabolic peptide world, and it is worth clearing up. There is no naturally occurring hormone called GLP-3 in the way there is a GLP-1. Instead, the term is used informally in research and marketing to describe the newest generation of metabolic peptides: the triple agonists, of which retatrutide is the flagship example. This guide explains the nomenclature and the science behind it.

Where the “GLP-3” name comes from

Metabolic peptides are usually named by the receptors they activate. The field evolved in generations:

• Single agonists such as semaglutide act on one receptor, GLP-1.
• Dual agonists such as tirzepatide add a second target, GIP.
• Triple agonists such as retatrutide add a third, glucagon.

Because each generation stacks another mechanism, some people reach for shorthand like “GLP-2” and “GLP-3” to signal how many pathways a compound hits. It is informal, GLP-3 is not an official receptor name, but it points at something real: the move toward multi-receptor peptides.

What a triple agonist actually does

Retatrutide, the compound most often meant by “GLP-3,” is engineered to activate three receptors at once:

The idea is that engaging three complementary pathways in a single molecule gives researchers a richer model than any single or dual agonist. Glucagon is the differentiator here, adding it to the incretin pair is what defines the triple-agonist class and separates retatrutide from its predecessors.

How the generations compare

If you see a product described as a “GLP-3” or “triple agonist,” it is almost certainly referring to retatrutide or a compound in the same class. Knowing the naming convention lets you cut through the marketing and identify exactly what you are looking at.

Why the naming matters when you buy

Because “GLP-3” is informal, the same compound can appear under several labels: retatrutide, triple agonist, or the GLP-3 shorthand. That ambiguity is exactly why it pays to know the receptor logic behind the names. When you understand that the defining feature of this class is the addition of glucagon to the incretin pair, you can look past whatever marketing term a listing uses and confirm you are getting the compound you actually want. Nomenclature fluency is a practical buying skill, not just trivia.

Handling and storage

Triple agonists ship as lyophilised powder, stable when kept cool, dark, and dry. Once reconstituted, keep the solution refrigerated, out of light, and away from repeated freeze-thaw cycles. Consistent handling is what keeps a metabolic peptide performing the same way from one lot to the next.

Sourcing triple agonists in Canada

The metabolic peptide field moves fast, and newer compounds are exactly where batch verification matters most. At LYFE Science every peptide is checked by HPLC and mass spectrometry, with a certificate of analysis available per lot so you know precisely what a batch contains.

We are a Canadian supplier shipping Canada-wide by Canada Post in neutral packaging. Shipping is a flat $25 and free over $150. Orders paid before noon ET typically dispatch the same day, reaching most of Canada in 1 to 3 business days. We accept Interac e-Transfer and crypto (BTC, ETH, SOL, USDC, USDT).

The takeaway

“GLP-3” is shorthand, not a real receptor, but it points to the triple-agonist generation led by retatrutide: three receptors, one molecule. As the metabolic field grows we add new compounds regularly, so browse the shop and read our peptide guide to understand the nomenclature before you buy.

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