Oleyl trifluoromethyl ketone is an analog of oleic acid in which the COOH group is replaced by trifluoromethyl ketone. It is a potent inhibitor of FAAH, in both human and rat. In transfected COS-7 cells, 10 μM oleyl trifluoromethyl ketone inhibits 95.7% of human FAAH activity and 94.8% of rat FAAH activity.