The medication is specifically approved, in the United States, for the treatment of hypogonadism in men, delayed puberty in boys, and breast cancer in women. It is also used in masculinizing hormone therapy for transgender men. Side effects
Side effects of testosterone enanthate include virilization among others. Approximately  10 percent of testosterone enanthate will be converted to dihydrotestosterone in normal men. Dihydrotestosterone (DHT) can promote masculine characteristics in both males and females. These masculine characteristics include: clitoral hypertrophy, androgenic alopecia, growth of body hair and deepening of the vocal cords. Dihydrotestosterone also plays an important role in male sexual function and may also be a contributing factor of ischemic priapism in males as shown in a study conducted on the use of finasteride to treat ischemic priapism in males. Testosterone enanthate can also lead to an increase in igf-1 and igf-bp. Testosterone enanthate can also be converted to estradiol by aromatase, which may lead to gynecomastia in males. Aromatase inhibitors can help to prevent the estrogenic activity of testosterone enanthate in the body. Pharmacology
Pharmacodynamics
Testosterone enanthate is a prodrug of testosterone and is an androgen and anabolic–androgenic steroid (AAS). That is, it is an agonist of the androgen receptor (AR). Pharmacokinetics
Testosterone enanthate has an elimination half-life of 4.5 days and a mean residence time of 8.5 days when used as a depot intramuscular injection. It requires frequent administration of approximately once per week, and large fluctuations in testosterone levels result with it, with levels initially being elevated and supraphysiological.
U.S. National Library of Medicine.