Used in research settings as a selective antagonist for the neurokinin-1 (NK1) receptor, helping scientists study substance P pathways involved in pain transmission, inflammation, and emotional behavior. It has been instrumental in exploring the role of tachykinins in neurological and psychiatric conditions such as anxiety, depression, and nausea. Due to its high selectivity, it serves as a valuable tool in pharmacological assays and in vivo studies to block NK1 receptor activity without significant off-target effects. Not intended for clinical or therapeutic use in humans.