(±)-Naproxen-d3, a deuterated form of naproxen, is primarily used in research and analytical applications. It serves as an internal standard in mass spectrometry and chromatography studies, particularly in pharmacokinetic and metabolic research. By using this deuterated compound, scientists can accurately quantify naproxen levels in biological samples, ensuring precise measurements due to its similar chemical properties but distinct mass. This aids in understanding drug metabolism, distribution, and excretion in the body. Additionally, it is employed in the development and validation of analytical methods for naproxen detection in pharmaceuticals and clinical studies.