Testosterone undecanoate, an ester of testosterone and one of the most widely used<unk> s. An<unk>  or anabolic steroid ester is an ester of an<unk> /anabolic steroid (AAS) such as the natural testosterone or dihydrotestosterone (DHT) or the synthetic nandrolone (19-nortestosterone). Esterification renders AAS into metabolism-resistant prohormones of themselves, improving oral bioavailability, increasing lipophilicity, and extending the elimination half-life (which necessitates less frequent administration). In addition, with intramuscular injection, AAS esters are absorbed more slowly into the body, further improving the elimination half-life. Aside from differences in pharmacokinetics (e.g., duration), these esters essentially have the same effects as the parent drugs. They are used in<unk>  replacement therapy (ART), among other indications. Examples of<unk> s include testosterone esters such as testosterone cypionate, testosterone enanthate, testosterone propionate, and testosterone undecanoate and nandrolone esters such as nandrolone decanoate and nandrolone phenylpropionate.
Androgen ester
Estrogen ester
Progestogen ester
17β-Aminoestrogen
Estrogen conjugate
Xenoestrogen
Catechol estrogen
Polyestradiol phosphate