Used as a stable isotope-labeled internal standard in mass spectrometry-based assays for the quantification of spermine in biological samples. Enables accurate measurement of polyamine metabolism in research related to cell growth, apoptosis, and cancer. Its deuterated butyl group provides a distinct mass shift, allowing clear differentiation from endogenous spermine during analytical detection. Commonly applied in metabolomics, clinical diagnostics, and pharmaceutical research where precise tracking of polyamine levels is required.