Testosterone Enanthate Injection, USP provides Testosterone Enanthate, a derivative of the primary endogenous androgen testosterone, for intramuscular administration. In their active form, androgens have a 17-beta-hydroxy group. Esterification of the 17-beta-hydroxy group increases the duration of action of testosterone; hydrolysis to free testosterone occurs in vivo. Each mL of sterile, colorless to pale yellow solution provides 200 mg Testosterone Enanthate in sesame oil with 5 mg chlorobutanol (chloral derivative) as a preservative.