Rasagiline 13C3 mesylate racemic is primarily used in research and development as a labeled compound for analytical purposes. Its isotopic labeling with carbon-13 (13C) makes it valuable in pharmacokinetic and metabolic studies, enabling researchers to track and quantify the compound and its metabolites in biological systems with high precision. This labeled form is particularly useful in mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, where it aids in understanding drug metabolism, distribution, and excretion pathways. Additionally, it serves as a reference standard in quality control and validation processes for pharmaceutical formulations containing rasagiline, ensuring accuracy and consistency in analytical measurements.