Used in research and clinical studies to investigate the role of vasopressin in various physiological processes. It serves as a stable isotope-labeled internal standard in mass spectrometry for accurate quantification of vasopressin levels in biological samples. This is particularly useful in studying conditions like diabetes insipidus, syndrome of inappropriate antidiuretic hormone secretion (SIADH), and other disorders related to water balance and blood pressure regulation. Additionally, it aids in understanding the pharmacokinetics and metabolism of vasopressin in therapeutic applications.