Hypertension is associated with endothelial dysfunction, an early event in the development of cardiovascular disease. Endothelial extracellular vesicles (EEVs) have emerged as promising biomarkers of endothelial activation and vascular injury; however, their relationship with blood pressure and microvascular endothelial function in untreated hypertension remains insufficiently understood. This observational case-control study aims to compare circulating EEV concentrations between normotensive adults and adults with newly diagnosed, untreated primary hypertension. In addition, the study will investigate the associations between EEV levels, blood pressure, microvascular endothelial function assessed by laser Doppler flowmetry, and established circulating biomarkers of endothelial activation. The findings may improve understanding of the role of EEVs in early hypertension and support their potential use as non-invasive biomarkers of endothelial dysfunction and cardiovascular risk.