Intradermal injections of platelet-rich plasma is proposed to be an effective treatment for androgenetic alopecia. The mechanisms by which platelet-rich plasma affects the hair follicle are still not well understood. The aim of the study was to evaluate the effect of platelet-rich plasma on the microcirculation and proliferative activity of hair follicle cells. The study included 25 men, all patients received intradermal injections of platelet-rich plasma. To obtain platelet-rich plasma, blood samples were collected from each patient into 2 tubes with an anticoagulant. Centrifugation was carried out twice. An official calcium chloride solution was used as an activator. The course of treatment consisted of 4 procedures with an interval of 4 weeks between each procedure. The clinical efficacy of the therapy was evaluated by the dynamics of morphometric indicators of hair growth. Immunohistochemical examination was performed on vertical paraffin sections. All studies were performed before and after 4 months after treatment. Against the background of treatment with platelet-rich plasma hair density and average hair diameter increased by 12% (p=0,000067 and p=0,001947 respectively), the share of vellus hair decreased by17% (p=0,002225), and the proportion of telogen hair by 16% (p=0,02836). Significant positive changes were absolute and relative values of CD34 expression area (∆287%, p=0,0001, and 325%, p=0,0003 respectively), and the absolute and relative values of the expression area of β-catenin (∆165%, p=0,0306 and ∆96%, p=0,0018, respectively). Thus, one of the mechanisms by platelet-rich plasma in patients with androgenetic alopecia is the improvement of microcirculation and cell proliferation of the hair follicle.