FAAH (fatty acid amide hydrolase) is a membrane-bound amidase that catalyzes the hydrolysis of endogenous amidated lipids, serving as the primary catabolic enzyme for endocannabinoids and related signaling molecules 1. The enzyme hydrolyzes anandamide (N-arachidonoylethanolamine) to arachidonic acid and ethanolamine, with preferential activity toward polyunsaturated substrates 1. FAAH also metabolizes oleamide (a sleep-inducing lipid) and 2-arachidonoylglycerol (2-AG), another endocannabinoid 1. The enzyme belongs to the amidase signature family and contains a catalytic serine residue 1. Beyond canonical substrates, bacterial FAAH variants regulate bioactive molecules including N-acyl amino acids and quorum-sensing molecules, affecting intestinal immune function 2. FAAH's role in endocannabinoid regulation has significant clinical implications. A common human polymorphism (C385A; rs324420) that reduces FAAH expression enhances fronto-amygdala connectivity and improves fear extinction learning while decreasing anxiety 3. Conversely, this variant associates with lower subjective well-being and increased alcohol dependence risk 4. FAAH inhibition shows therapeutic potential for migraine through CB1 receptor-mediated anti-nociceptive effects in meningeal tissues 5. Additionally, loss-of-function FAAH mutations interact with DGAT2 variants in obesity development 6, while the rs324420 polymorphism associates with generalized epilepsy susceptibility 7. These findings suggest FAAH modulation as a therapeutic target, though previous adverse events in clinical trials warrant careful development 8.