Testosterone enanthate is an oil based injectable steroid, designed to slowly release testosterone from the injection site (depot). Once administered, serum concentrations of this hormone will rise for several days, and remain markedly elevated for approximately two weeks. It may actually take three weeks for the action of this drug to fully diminish. For medical purposes this is the most widely prescribed testosterone, used regularly to treat cases of hypogonadism and other disorders related to androgen deficiency. Since patients generally do not selfadminister such injections, a long acting steroid like this is a very welcome item.