Zymosterol-d5 is primarily used as an internal standard in analytical chemistry, particularly in lipidomics and sterol metabolism studies. Its deuterated structure allows for precise quantification of zymosterol and related sterols in complex biological samples using techniques like mass spectrometry. This compound aids researchers in understanding cholesterol biosynthesis pathways and identifying metabolic disorders. It is also employed in drug development to study the efficacy of compounds targeting sterol metabolism. Additionally, zymosterol-d5 is valuable in clinical research for investigating biomarkers associated with diseases such as cancer and cardiovascular conditions. Its stable isotopic labeling ensures accurate and reliable results in high-throughput screening and diagnostic assays.