Introduction. Androgens play a key role in the male development. All the physiological processes in the body, including the production of testosterone, have their chronobiological features. Aging is accompanied by a disruption in the regulation of chronobiological processes. With androgen deficiency, these changes occur at any age. In recent years, transdermal forms of testosterone have become very popular in the treatment of this condition.
Aim. To evaluate the effectiveness and chronobiological features of various regimens of testosterone gel therapy for external use in men with androgen deficiency.
Materials and methods. The study comprised 90 men aged 45 to 60 years with testosterone deficiency. Patients were randomized into three groups of 30 people each. In group I (control) patients received basic therapy, including exercise, diet, and multivitamins. In group II, patients received basic therapy concurrently with testosterone gel for external use (Androgel) at a daily dose of 5 g (1 sachet). Patients in group III were administered basic therapy in combination with 10 g testosterone (2 sachets). The effectiveness of treatment was assessed at 3 (visit 2) and 6 (visit 3) months. Depending on the results of visit 2, a correction of therapy was carried out, if necessary. During each visit, the patients underwent evaluation, including hematocrit, levels of FSH, LH, prolactin, total testosterone, blood SHBG, waist circumference, and body weight. Patients completed the ICEF-5 questionnaire, the Hamilton scale (HDRS, HARS), and the SF-36 questionnaire. We also tested the patients for the chronobiological status and desynchronosis.
Results. During the visit I, the homogeneity of the study population was confirmed. At three months, the patients of groups II and III showed a more pronounced increase in testosterone, a decrease in body weight and waist circumference, as well as an improvement in the psycho-emotional status and quality of life according to the questionnaires. Desynchronosis persisted in 25 (83.3%), 9 (30%), and 4 (13.3%) patients in groups I, II, and III, respectively. Given the findings, the treatment was adjusted. The patients in the groups were divided into subgroups A and B. In subgroups A, patients continued to receive initial therapy, and in subgroups B, the treatment was adjusted. At six months, the level of GT increased to normal values in all subgroups except subgroup IA. The most marked reduction in body weight and waist circumference was noted in subgroups IA, IIA, and IIIB. A significant decrease in the average scores on the HDRS and HARS scales and an improvement in the SF-36 scale were observed in the subgroups IA, IIA, IIIB. Desynchronosis persisted in 3, 2, and one patient in subgroups IB, IIB, and IIIA.
Conclusion. The testosterone gel therapy in patients with androgen deficiency can effectively reverse the manifestations of the disease and normalize the chronorhythm. Transdermal testosterone gel at a daily dose of 5 g in the morning can be recommended to alleviate clinical manifestations of the disease and eliminate desynchronosis in this category of patients. In patients with low baseline testosterone levels, it is advisable to administer the drug at a daily dose of 10 g.

Keywords: testosterone gel, chronorhythm, desynchronosis, androgen deficiency, testosterone