Prostaglandin E1-d4 is widely used in biomedical research as a deuterium-labeled internal standard for the quantification of prostaglandin E1 in biological samples. Its application is crucial in mass spectrometry-based assays, ensuring accurate and precise measurement of prostaglandin E1 levels in studies related to inflammation, cardiovascular health, and reproductive biology. The deuterium labeling allows for differentiation from endogenous prostaglandin E1, enhancing the reliability of analytical results. Additionally, it aids in pharmacokinetic and pharmacodynamic studies, providing insights into drug metabolism and therapeutic efficacy.