d[Cha4]-AVP TFA is a potent and selective agonist for the vasopressin (AVP) V1b receptor, displaying a high affinity with a K i of 1.2 nM. It exhibits greater selectivity for the V1b receptor over the V1a receptor, V2 receptor, and oxytocin receptors, demonstrating its specificity in targeting the human V1b receptor [1] [2].