Glossary · Pharmacology
Agonist and antagonist
In short
An agonist binds to a receptor and triggers a signal there; an antagonist occupies the receptor and blocks the signal. Many active substances can be described with this pair of terms.
A receptor is a docking site, usually a protein on or in the cell, that fits one of the body’s own messengers. An agonist mimics this messenger, an antagonist keeps it away. In between there are partial agonists, which trigger only a weaker signal, and modulators, which act differently depending on the tissue.
That a substance binds to a receptor in the lab is a mechanism — not yet an effect in humans. In the BK-Score this feeds into the mechanism axis; whether a benefit follows is measured by human evidence.
The agonist switches on, the antagonist blocks.
Where this comes up in the fact checks
- Tirzepatide – Activates two gut hormone receptors at the same time.
- Orexin receptor antagonists – Sleep medicines that block the wakefulness signal orexin at its receptor.
- Cabergoline – A dopamine agonist that reliably lowers excessive prolactin levels.
- Ostarine – Activates the androgen receptor, the docking site of testosterone.
Related terms: SARM · Peptide · Half-life
Information only, not medical advice. The BK-Score is a subjective assessment according to disclosed rules – not a scientific evaluation. Scoring rules