N-?Oleoylethanolamide-d4 is the labeled analogue of N-?Oleoylethanolamide (O527280), an agonist of peroxisome proliferator-activated receptor-α (PPAR-?α). N-?Oleoylethanolamide generates an intestinal signal that stimulates central dopamine activity establishing a link between caloric-?homeostatic and hedonic-?homeostatic controllers. N-?Oleoylethanolamide-d4 is a selective GPR55 agonist.