Testosterone enanthate is used in androgen substitution to replace testosterone at levels as close to physiological levels as is possible. For some androgen-dependent functions testosterone is a pro-hormone, peripherally converted to 5alpha-dihydrotestosterone (DHT) and 17beta-estradiol (E2), of which the levels preferably should be within normal physiological ranges. Furthermore, androgens should have a good safety profile without adverse effects on the prostate, serum lipids, liver or respiratory function, and they must be convenient to use and patient-friendly, with a relative independence from medical services. Natural testosterone is viewed as the best androgen for substitution in hypogonadal men. testosterone enanthate is used to treat male hypogonadism. Male hypogonadism is one of the most common endocrinologic syndromes. The diagnosis is based on clinical signs and symptoms plus laboratory confirmation via the measurement of low morning testosterone levels on two different occasions. Serum luteinizing hormone and follicle-stimulating hormone levels distinguish between primary (hypergonadotropic) and secondary (hypogonadotropic) hypogonadism. Osteoporosis in male hypogonadism: responses to androgen substitution differ among men with primary and secondary hypogonadism. In primary hypogonadal men the on bone mineral density (BMD) responds dose dependently to testosterone substitution, whereas in secondary hypogonadism only testosterone enanthate treatment significantly increased the BMD. In all mammalian species studied to date, testosterone has been found to be the predominant intratesticular steroid. In volunteers receiving hormonal contraception by using a combination of testosterone enanthate and levonorgestrel, there is a profound reduction of both intratesticular testosterone concentration and androgen bioactivity. High doses of testosterone enanthate can normalize hematocrit values of maintenance hemodialysis patients with replenished bone marrow iron stores. testosterone enanthate is classified as a prohibited substance by the World Anti-Doping Agency (WADA) and its use may be detected by way of the urinary testosterone/epitestosterone (T/E) ratio. (PMID: 16185098, 16467270, 15329035, 17530941, 17484401, 4028529, 12792150).