Difference Between Agonist and Antagonist

Main Difference – Agonist vs Antagonist

Agonist and Antagonist are two contradictory terms, i.e., they are antonyms. These two terms also have different meanings in different fields. The terms, agonists and antagonists are mainly found in the fields of anatomy, biochemistry and literature. As mentioned above, agonist and antagonist act in opposite ways; when an agonist produces an action, antagonist produces its opposite action. This is the main difference between agonist and antagonist.

Agonist – Meaning and Usage

As mentioned earlier, agonist has different meanings. When we are talking about the human body, however, agonist is a muscle. This muscle’s contraction helps to move a part of the body directly. In biochemistry, agonist is a substance which initiates a physiological response when combined with a receptor. In pharmacology, agonist is a drug which imitates the action of neurotransmitters in the brain.

In literature, agonist is the equivalent of a protagonist. Agonist refers to the leading character of a book, play, drama, etc. For example, Harry Potter is the agonist of the Harry Potter series.

Main Difference - Agonist vs Antagonist

Oliver is the protagonist (agonist) in Charles Dicken’s Oliver Twist.

Antagonist – Meaning and Usage

Antagonist too has many different meanings, just like agonist. But what is interesting about this term is that it has the exact opposite meanings from agonist.

In anatomy, antagonist is a muscle whose action counteracts that of an agonist muscle. Agonist and Antagonist muscles usually occur in pairs; when one muscle relaxes, the other contracts. Biceps and triceps are an example of this kind of muscle pair.

Since the chemical agonist instigates a physiological response when combined with a receptor, antagonist does the exact opposite; antagonist inhibits or interferes with the physiological response of agonist.

As a drug, antagonists block the neurotransmitters in the brain. This is in contrast to the action of agonists: mimicking the effects of neurotransmitters.

As seen from all the above meanings, it becomes clear that agonists produce an action, or a reaction and antagonists produce its opposite action.

Antagonist has another meaning, which is perhaps the most common meaning of this word. An antagonist is a person who opposes something or is hostile to something or someone. In literature, antagonist is the main opposing force of the protagonist. Difference Between Agonist and Antagonist

Difference Between Agonist and Antagonist


Agonist produces an action or response.

Antagonist produces its opposite action or response.


Agonist is a muscle whose contraction moves a part of the body directly.

Antagonist is a muscle whose action counteracts that of agonist.


Agonist is a substance which initiates a physiological response when combined with a receptor.

Antagonist is a substance which interferes with or inhibits the physiological action of another.


Agonist is a drug which imitates the action of neurotransmitters in the brain.

Antagonist is a drug that blocks neurotransmitters.


Agonist is the leading character in a literary work.

Antagonist is the main opposing force of the protagonist.Difference Between Agonist and Antagonist- infographic

Image Courtesy:

“Oliver Twist” by George Cruikshank – Oliver Twist by Charles Dickens via Folio Society (Public Domain) via

“Villain” by J.J. at the English language Wikipedia via

About the Author: admin

Related pages

invoke evokecalculate centripetal accelerationcystinesdifference between cytosol and cytoplasmdifference tortoise and turtleroman law vs common lawevoke vs invokedifference between retin a and retinolprokaryotic and eukaryotic transcriptionwhat is the difference between a tornado and a cycloneporcelain ceramic differencesushi sashimi nigiri differencedifference between marginal costing and absorption costingdifference between associates and bachelorspolyunsaturated fat vs monounsaturatedcpap and bipap differencedifference between sherbert and sorbetdifference between stomach flu and food poisoningthe moral of little red riding hoodliteral language vs figurative languagedefinition of coefficient of kinetic frictionwhat is interrogative pronoundifference between baking soda and cooking sodaisle aislehoney badger furdifference between endnotes and works citedschizoaffective disorder and schizophrenia differencewhat does protoplasm dowhat's the definition of cytoplasmgnostic and agnosticdifferentiate between alleles and genesprotagonists and antagonistsmeiosis and mitosis differencewhat is the difference between a mile and a kilometerinternal rimedifference between self raising flour and all purpose flourdifference between elevation and altitudeindian judiciary structurepolyps vs cystsnitrates vs nitritesnik naks definitionlysosome peroxisomewhat is dynamic viscosity and kinematic viscositymeaning of the word aspiremoral lesson of the good samaritanmolecular weight hexaneldpe or hdpedefinition of catabolism and anabolismwhat is oogenesisstem cells totipotent pluripotent multipotentvascular and non vascularaction verb and linking verbwhat is warm blooded meandifference between epidural and spinalcrepe pancakesadvantages of digital multimeter over analog multimeterdifference between straightening and smoothingamerican trouserdifference between phoneme and morphemedefine noun clauseprosperous means in hindiare parsley and cilantro the sameexample of consonant soundpeasants and serfs in the middle ageslow comedy definitionsynecdoche meaning and examplesstanzas and versesnovel vs novelladysponea definitionwhat is the difference between chromatid and centromerequantum theory vs string theorycpi index calculationsatire and sarcasmwhat is the difference between tradeoff and opportunity costdifference between diode and transistorwhat is the difference between a hotel and a motellinking verb vs helping verbshelley famous poemsmicrometer screw gauge usestelomere centromere