Oleoyl ethanolamide-d2 (OEA-d2) is intended for use as an internal standard for the quantification of OEA by GC- or LC-MS. OEA is an analogue of the endocannabinoid arachidonoyl ethanolamide (AEA) found in brain tissue and in chocolate.¹ It is one of the long chain fatty acid ethanolamides that accumulates rapidly in infarcted tissue, but its biosynthesis is reduced in the intestine of rats following food deprivation.^2,3 OEA is an endogenous, potent agonist for peroxisome proliferator-activated receptor α (PPARα), exhibiting an EC50 value of 120 nM in a transactivation assay.⁴ Systemic administration of OEA suppresses food intake and reduces weight gain in rats (10 mg/kg intraperitoneally) and PPARα wild-type mice, but not in PPARα knockout mice.^3,4 These data indicate that OEA regulates food intake by a PPARα-mediated mechanism.