Context: Endothelial microparticles (EMPs) are novel, surrogate biomarkers of endothelial function and have been shown to be elevated in women with polycystic ovary syndrome (PCOS). It remains poorly understood how pharmacological options for managing PCOS affect EMP levels. Objective: To characterise and compare the effects of empagliflozin vs metformin on the circulating levels of EMPs in overweight/obese women with PCOS.