Treating symptoms of low testosterone in men when the body does not make any testosterone or not enough testosterone (hypogonadism). It may also be used for other conditions as determined by your doctor. It is also used to treat certain types of breast cancer in women.Testosterone enanthate is a male sex hormone. It works by replacing or supplementing the testosterone that is naturally made in the body. It also counteracts the effects of estrogen in certain types of breast cancer, which helps to decrease cancer growth.