IC50 and EC50 difference

The terms IC50 and EC50 are both used in pharmacology and toxicology to describe the potency of a compound, but they refer to different types of biological effects and are measured in different contexts:

IC50 (Inhibitory Concentration 50):

IC50 represents the concentration of a drug or compound required to inhibit a specific biological or biochemical function by 50%.

It is commonly used in enzyme inhibition assays or in assays where the goal is to inhibit a particular physiological process, such as cell proliferation or enzyme activity.

Lower IC50 values indicate higher potency, meaning that less of the compound is needed to achieve the desired inhibition.

EC50 (Effective Concentration 50):

EC50 represents the concentration of a drug or compound required to produce a specific effect or response halfway between the baseline and maximum after a specified exposure time.

It is commonly used in dose-response experiments where the goal is to measure the concentration of a compound needed to elicit a particular biological response.

Like IC50, lower EC50 values indicate higher potency, meaning that less of the compound is needed to produce the desired effect.

In summary, while both IC50 and EC50 represent concentrations of a compound, IC50 specifically denotes inhibition of a biological function by 50%, while EC50 represents the concentration needed to produce a biological effect or response by 50%. 

They are often used in different types of experiments but serve similar purposes in quantifying the potency of compounds.