INTRODUCTION Decreasing of testosterone level is an important part of a male elderly. MATERIAL AND METHODS To describe this phenomenon a PubMed and national databases were searched for 17β-dehydrotestosterone, common testosterone, free testosterone, 17β-estradiol, luteinizing hormone, partial androgen deficiency of aging men. RESULTS The reduction in intensity of the processes of tissue renewal of the testicles results in a partial androgen deficiency of aging men. A decrease in the levels of total and free testosterone and an increase in the levels of 5α-dihydrotestosterone, 17β-estradiol, sex hormone binding globulin, LH and FSH, along with a decrease in the amplitude of the rhythm of incretion of LH, FSH and total testosterone will testify to a deficiency of testosterone. CONCLUSIONS It is very important to make an individualized selection of the dose of testosterone preparation which enters the blood plasma.