An agonist is a peptide (or other molecule) that binds a receptor and activates it, triggering a response. An antagonist, by contrast, binds the receptor but blocks the response. The word describes what a peptide does once it reaches its target.
Agonist vs. antagonist
Recall that many peptides work by binding receptors on cells. An agonist is the type that switches the receptor on: it is a key that both fits the lock and turns it. An antagonist fits the lock but does not turn it, and can block others from doing so.
Why the label appears so often
Many research peptides are named by what they activate. A GLP-1 receptor agonist activates the GLP-1 receptor; a melanocortin receptor agonist activates melanocortin receptors. The agonist label tells you the peptide is designed to trigger a response at that target.
Single, dual, and triple agonists
Some peptides are agonists at more than one receptor. This is where terms like single, dual, and triple agonist come from, describing how many receptors a peptide activates.
Key takeaways
- An agonist binds a receptor and activates it.
- An antagonist binds but blocks the response.
- Many peptides are named for the receptor they activate.
- Some are agonists at more than one receptor (dual, triple).
A note on research use
The peptides supplied by Axis Peptide Labs are reference compounds for laboratory and research use only. They are intended for qualified researchers working in academic, institutional, and analytical settings. They are not drugs, foods, cosmetics, or medical products, and they are not intended for human or veterinary consumption. Documented identity and documented purity are what matter most when sourcing a compound, both of which are published on the Axis certificates of analysis page.
