6-keto Prostaglandin F1α-d4 is primarily used as an internal standard in analytical chemistry, particularly in mass spectrometry and liquid chromatography-mass spectrometry (LC-MS) applications. It aids in the accurate quantification of endogenous 6-keto Prostaglandin F1α, a stable metabolite of prostacyclin, in biological samples. This is crucial for research involving cardiovascular health, inflammation, and vascular function, as prostacyclin plays a significant role in these processes. The deuterated form ensures precise measurement by minimizing interference from naturally occurring isotopes. Additionally, it is employed in pharmacokinetic and metabolic studies to understand drug interactions and pathways related to prostacyclin metabolism.