The presence of metabolic syndrome (MS) increases the risk of atherosclerotic cardiovascular disease and type 2 diabetes. Correction of MS manifestations is important for reducing cardiovascular risk. The aim is to study the effect of using a composition of nanoparticles of iron oxide, quercetin and ascorbic acid in women with MS. Materials and methods. 60 women with MS were divided equally into the main and control groups. Patients of the main group received a composition of dietary supplement Lizoferrin (iron oxide nanoparticles, quercetin and ascorbic acid), patients of the control group received a placebo. Anthropometric indicators, fasting blood glucose concentration and 2 h after oral glucose tolerance test, fasting blood serum lipids, microvascular endothelium function were determined before and 1 month after use of Lizoferrin or placebo. Results. The use of dietary supplement Lisoferrin led to a decrease in fasting blood glucose and 2 hours after a standard oral glucose tolerance test, total cholesterol and low-density lipoprotein serum concentrations in subjects with atherogenic dyslipidemia. Along with this, an improvement in the functional state of the endothelium of microvessels was noted, as evidenced by an increase in the maximum volume velocity of skin blood flow in a test with reactive hyperemia. Conclusion. A placebo-controlled study for the first time demonstrated the beneficial effect of a combination of iron oxide nanoparticles, quercetin, and ascorbic acid on cardiovascular risk factors in patients with MS.