The amount of product required depends on many factors: This includes target accessibility, cell permeability, duration of incubation, and type of cells or assay used; it is best to survey the literature to determine the IC50, EC50, or Ki. For an inhibitor, if published Ki or, IC50 values are known, we recommend that you use five to 10 times higher than these values to maximally inhibit enzyme or receptor activity. If there are no published values, we recommend that you perform dose-response experiments (running appropriate controls) and use Michaelis-Menten kinetics to determine the Ki value.