BIBP-3226 is a drug used in scientific research which acts as a potent and selective antagonist for both the Neuropeptide Y receptor Y<sub>1</sub> and also the neuropeptide FF receptor. It was the first non-peptide antagonist developed for the Y<sub>1</sub> receptor and has been widely used to help determine its functions in the body. Activation of Y<sub>1</sub> is thought to be involved in functions such as regulation of appetite and anxiety, and BIBP-3226 has anxiogenic and anorectic effects, as well as blocking the Y<sub>1</sub>-mediated corticotropin releasing hormone release. It has also been used as a lead compound to develop a number of newer more potent Y<sub>1</sub> antagonists.