The level of testosterone in men fluctuates and is highest in the morning hours, so it is recommended to take a blood sample within two hours after waking up[1][3]. Among young men aged 17 to 30, 62% of 11,901 tests from January 2023 to September 2024 showed lower than recommended testosterone levels[2]. Testosterone is essential for the development of the male phenotype in the embryonic period, the descent of the testicles into the scrotum and the emergence of secondary sexual characteristics at puberty[1]. Testosterone deficiency can cause delayed puberty in boys over 14 years of age or pseudopuberty before the age of 9[1]. Factors such as smoking, alcohol, lack of sleep, stress and obesity reduce testosterone levels[1][2][6]. Low levels affect fertility through sperm production and can contribute to obesity, metabolic syndrome, and type 2 diabetes[2][4]. When suspected, diagnosis is made by history, physical examination and laboratory tests including total testosterone, SHBG, LH and FSH[3]. It is recommended to visit an endocrinologist or urologist[2].