The word behind the drug class
Nearly every GLP-1 medication has “agonist” in its formal description — Ozempic and Wegovy are GLP-1 receptor agonists, and Zepbound is a dual GIP/GLP-1 receptor agonist. The term comes straight from pharmacology: an agonist is anything that binds to a receptor (a docking site on a cell) and activates it, kicking off a biological response.
Agonist vs. antagonist
The mirror image is an antagonist, which occupies a receptor without activating it — effectively blocking the signal. GLP-1 drugs are firmly on the agonist side: they switch the GLP-1 receptor on, imitating the natural incretin hormone your gut makes after a meal. That activation is what lowers blood sugar and dials down appetite.
So when you see “GLP-1 receptor agonist,” you can read it plainly: a drug that turns on the GLP-1 receptor. A “dual agonist” turns on two receptor types at once; a “triple agonist” adds a third. The number just tells you how many of these switches the molecule flips.