Testosterone enanthate is a testosterone replacement therapy. It's mainly used in males to treat low testosterone levels and delayed puberty. It's also FDA-approved in females for treating metastatic breast cancer, but it's not a first-choice option for this condition. Testosterone enanthate is given as a deep injection into the muscle of the buttock, typically every 2 to 4 weeks by a healthcare professional (HCP). Side effects can include acne and pain or swelling at the injection site.