The article describes the historical decline and subsequent resurgence of medical interest in testosterone. In the 20th century, testosterone was discovered and rapidly used in a variety of medical and performance contexts, with the isolation of the hormone dating back to around 1935[3]. Later, testosterone and anabolic steroids also spread into sports and commercial abuse, leading to concern and regulation of their use[3][2]. However, medical use remained legitimate in the treatment of hormonal disorders, delayed puberty, and loss of muscle mass in some diseases[5]. Currently, interest has returned as a result of new studies examining the effects of replacement therapy in elderly men and in patients with low testosterone levels[4]. The article also highlights that there remain many unanswered questions about testosterone regarding its metabolism and effects in the brain[6]. When statistics or specific studies are mentioned in the text, the article mentions randomized and controlled trials examining the effects of testosterone replacement on muscle performance and function in older men[4].