Background: Endothelial dysfunction is the first but reversible stage of atherosclerosis. A change in the functional state of the vascular endothelium, especially of a growing organism, can be the basis for the development of many diseases in adulthood. The study of the structural and functional state of peripheral vessels of adolescents with hypothalamic syndrome is extremely important for understanding of the mechanisms of formation of cardiometabolic risks.Aims: to compare the structural and functional state of the vascular wall of young men with hypothalamic syndrome and constitutionally exogenous obesity.Methods: During the study 360 males were examined (average age 21.27±2.44 years) and divided into 3 groups: group 1 -with hypothalamic syndrome (n=242); group 2 - with constitutionally exogenous obesity (n=98); control group - practically healthy individuals (n=20). Hypothalamic syndrome was verified in the presence of a symptom complex, including obesity and pink striae. Cross-group comparative analysis of results of clinical, laboratory and instrumental examination was carried out.Results: In the group of patients with hypothalamic syndrome, endothelium-dependent vasodilatation (9.44±1.26 versus 10.37±1.21%; p=0.001) and endothelium-independent vasodilatation (10.29±1.28 versus 11.29±1.14%; p=0.001) is worse than in the group of patients with constitutionally exogenous obesity, and the rate of endothelium-dependent vasodilatation is lower than the generally accepted norm. In addition, among patients with hypothalamic syndrome, the stiffness of the vascular wall is higher than among patients with constitutionally exogenous obesity (15.47±2.58 versus 13.24±3.84%; p=0.001). Statistically significant correlations were revealed between the structural and functional state of peripheral arteries and hemodynamic, hormonal, metabolic changes, and the level of C-reactive protein (p<0.05).Conclusions: The obtained data indicate a deterioration of endothelial function and an increase in vascular wall stiffness in obese patients, regardless of its etiology. The patients with hypothalamic syndrome have more pronounced structural and functional changes in the vascular wall are observed than patients with constitutionally exogenous obesity.