Barbadin is a novel and specific inhibitor of beta-arrestin/beta2-adaptin interaction with an IC50 value of 19.1 uM for beta-arestin1 and 15.6 uM for beta-arestin2. Barbadin potentiates the long term effects of lorcaserin on POMC neurons and weight loss. Barbadin potentiates the long-term effects of lorcaserin on POMC neurons and weight loss, blocks agonist-promoted endocytosis of prototypic beta2-adrenergic, V2-vasopressin, and angiotensin-II-1 receptors, and may be useful in the study of obesity.