Used as a stable isotope-labeled internal standard in mass spectrometry and metabolic studies to accurately quantify neurotransmitters and related metabolites. Its deuterated structure allows for clear differentiation from non-labeled compounds in biological samples, enhancing measurement precision. Commonly applied in research involving polyamine metabolism, including studies on cell growth, apoptosis, and oxidative stress. Also utilized in pharmaceutical development for tracing metabolic pathways and assessing drug interactions involving diamine compounds.