<unk> , or testosterone 17β-undecanoate, is a synthetic androstane steroid and a derivative of testosterone. It is an androgen ester; specifically, it is the C17β undecylate<unk>  ester of testosterone. A related testosterone ester with a similarly very long duration is testosterone buciclate.
Testosterone undecanoate
Testosterone decanoate
Testosterone acetate
Testosterone furoate
Testosterone propionate
Testosterone enanthate
Testosterone undecylenate
Testosterone valerate