(S)-KT109 is the (S) isomer of the diacylglycerol lipase β (DAGLβ) inhibitor KT109 . (S)-KT109 is a less potent inhibitor of DAGLβ (IC50 = 39.81 nM), DAGLα-mediated hydrolysis of 1-stearoyl-2-arachidonoyl-sn-glycerol (IC50 = 794.3 nM), and α/β-hydrolase domain-containing protein 6 (ABHD6; IC50 = 630.9 nM) than (R)-KT109 .