Aspartame-d3 is primarily used in research and analytical applications as a labeled internal standard. It is employed in mass spectrometry and other analytical techniques to quantify and study the metabolism of aspartame in biological samples. The deuterium labeling allows for precise tracking and differentiation from non-labeled aspartame, ensuring accurate measurements in pharmacokinetic and metabolic studies. This compound is particularly useful in food science and toxicology research, where understanding the breakdown and effects of aspartame in the body is critical. Its application aids in developing safer food additives and assessing potential health impacts.