Common Esters Available for Testosterone Injections

Below is a discussion of common testosterone esters. The primary difference between esters is the rate at which testosterone enters the bloodstream following an injection. A slower release means fewer testosterone injections per year. Testosterone propionate is a fast-acting ester rarely used in TRT. Testosterone enanthate and testosterone cypionate are slow-acting injectable forms. They have been the predominant form used for TRT. Testosterone undecanoate is a newly approved form that is very slow-acting.