Testosterone Enanthate (MUTANT TEST E 300) is an injectable steroid in oil, designed to release testosterone slowly from the moment of injection.
Once administered, serum concentrations of this hormone will increase for several days and remain elevated for approximately two weeks. It may take three weeks for the action of this drug to wear off completely.
For medical purposes this is the most widely prescribed testosterone, regularly used to treat cases of hypogonadism and other disorders related to androgen deficiency.
Although this particular testosterone enanthate ester is active for much longer, most athletes prefer to inject it weekly to keep blood levels more even.