Mangostin-d3 is primarily utilized in research and analytical studies as a stable isotope-labeled compound. It serves as an internal standard in mass spectrometry for the accurate quantification of mangostin and its metabolites in biological samples. This application is crucial in pharmacokinetic studies, where precise measurement of drug concentrations in plasma, urine, or tissues is required. Additionally, it aids in the development and validation of analytical methods, ensuring reliability and reproducibility in detecting mangostin-related compounds. Its use enhances the understanding of the absorption, distribution, metabolism, and excretion of mangostin, contributing to advancements in pharmacology and natural product research.