β-Tocopherol-d3 is primarily used in research and analytical applications as an internal standard for the quantification of tocopherols in various samples. It is particularly valuable in mass spectrometry and chromatography studies, where its deuterated structure allows for precise measurement and differentiation from non-deuterated tocopherols. This compound aids in the accurate analysis of vitamin E levels in biological samples, such as blood, tissues, and food products, ensuring reliable data for nutritional and clinical studies. Additionally, it supports investigations into the antioxidant properties and metabolic pathways of tocopherols in living systems.