Introduction. A significant reason for the decrease in the effectiveness of testosterone replacement therapy (TRT) in men is the increased activity of the aromatase enzyme in overweight and obese patients, when under its influence estrogens are converted from androgens (the transition of testosterone to estradiol) mainly in adipose tissue, leading to an increase in estradiol levels. That is, with exogenous administration of testosterone, estradiol becomes overabundant, thereby the positive effects of TRT are weakened and even often leveled, dangerous side effects of hyperestradiolemia appear, that is, without careful monitoring and normalization of estradiol levels, the effectiveness of TRT turns out to be low, and the side effect of therapy, due to high estrogens, on the body is high.

The aim of research was to increase the effectiveness of testosterone replacement therapy for hypogonadism in obese patients.

Material and methods. A two-center prospective study was conducted to study TRT for hypogonadism. The results of examination and treatment of 106 men aged 35-59 years (average age 45.9±7.2 years) with hypogonadism syndrome, who were prescribed TRT Omnadren 250 mg 1 ml/m, were analyzed. The levels of total testosterone, estradiol, and prolactin were monitored 48 hours after injection (Omnadren pharmacokinetics: Cmax of testosterone in blood plasma occurs within 24-48 hours), as well as level of hormones on day 10 with Aging Male Screening (AMS) control.

Results. In patients with TRT, on the second day after 48 hours, as well as after 10 days inclusive, an increase in testosterone and estradiol was statistically significant (p<0.01), but in overweight and obese individuals, the aromatization of testosterone into estradiol was significantly higher than in patients with normal body mass index (BMI), with at the same time, according to the scores of the AMS questionnaire, there was an improvement clinically, however, in patients with obesity it was clinically less significant due to significantly increased level of estradiol at the time of treatment.

Conclusions. It was found that patients with increased BMI have worse treatment results with elevated estradiol, which requires monitoring of estradiol starting from 2-3 days and later on day 10 in order to titrate the frequency of injections of testosterone preparations and correct the level of estradiol to physiological ones.