1-Palmitoyl-D9-2-hydroxy-sn-glycero-3-PE serves as an internal standard for quantifying 1-palmitoyl-2-hydroxy-sn-glycero-3-PE,a lysophospholipid naturally found to inhibit L. donovani promastigotes growth (GI50= 8 µM). Its levels are reduced in mice after alcohol-induced liver damage,in hepatocellular carcinoma mouse xenografts,and in humans following a rigorous three-day exercise regimen of 2.5 hours running daily and 14 hours post-regimen. This compound is also applied in measuring saturated lysophosphoethanolamines,highlighting its broad utility in biochemical research and disease model studies.