CAY10508 is a potent and selective inverse agonist for the central cannabinoid (CB1) receptor with therapeutic potential for treating obesity and drug dependence, lacking psychotropic effects. It exhibits a Ki value of 243 nM and an EC50 of 195 nM. At a concentration of 10 µM, CAY10508 displaces [3H]-CP-55,940 with 100% efficacy at the CB1 receptor and 35% at the peripheral cannabinoid (CB2) receptor. Its inverse agonist activity at the CB1 receptor was confirmed through a [35S]-GTPγS binding assay.