What is EC50?

EC₅₀ (also written as [A]₅₀) stands for half maximal effective concentration. It is a measure of the concentration of a drug at which 50% of its maximal response is induced and can be determined from the inflection point where the rate of increase in response with respect to the ligand concentration goes down. EC₅₀ and IC₅₀, albeit conceptually similar, have differences in their notions. For a better understanding, check out what is the difference between EC50 and IC50.