Agonist
An agonist is a compound that binds to a receptor and activates it, producing a biological response. GLP-1 agonists like Semaglutide mimic the activity of natural GLP-1 by binding and activating the GLP-1 receptor.
Overview
Agonists produce a response by binding to a receptor and stabilizing it in its active conformation, triggering downstream signaling. A full agonist produces the maximum possible response at that receptor; a partial agonist produces a submaximal response even at full receptor occupancy. The concept of agonism is central to understanding most research peptides: GHRH analogues are GHRH receptor agonists, GHRPs are ghrelin receptor agonists, GLP-1 receptor agonists mimic GLP-1, and melanocortin peptides are melanocortin receptor agonists. The potency of an agonist is described by its EC50 (the concentration that produces 50% of maximum effect), and its maximum effect by its Emax.
Related Terms
Related Peptide Profiles
Frequently asked questions
What is the difference between a full agonist and a partial agonist?+
A full agonist produces the maximum receptor response when it binds. A partial agonist produces a submaximal response even at full receptor occupancy — it activates but less completely than a full agonist.
Are all research peptides agonists?+
Most research peptides of interest are agonists that mimic or amplify endogenous signaling. Some peptides are studied as receptor antagonists that block natural ligand binding.
What does 'selective agonist' mean?+
A selective agonist preferentially binds one receptor subtype over others, producing more targeted effects with fewer off-target actions. Ipamorelin's selectivity for the GH-stimulating ghrelin receptor with minimal cortisol/prolactin effects is an example.