Fatty acid amide hydrolase (FAAH), an enzyme responsible for the hydrolysis and inactivation of fatty acid amides like anandamide and oleamide, has been identified as a target by the potent FAAH inhibitor PHOP. PHOP demonstrates remarkable inhibitory activity with K_i values as low as 0.094 nM for human FAAH and 0.2 nM for rat FAAH. Additionally, through a proteomics assay focusing on the serine hydrolase enzyme family, to which FAAH belongs, PHOP's selectivity was evaluated, presenting IC_50 values of 1.1 nM against FAAH, 1.4 nM against triacylglycerol hydrolase (TGH), and greater than 100 µM against an uncharacterized hydrolase (KIAA1363). This specificity profile of PHOP underscores its potential for yielding precise outcomes in studies involving complex biological systems.