In developing males, taking testosterone undecanoate can promote the development of short penis due to androgen deficiency, but for males with fully developed penis, it cannot achieve the purpose of penis enlargement. Testosterone undecanoate is a kind of sex hormone, clinically applicable to exogenous supplementation of male androgen deficiency and other diseases, for the lack of androgen caused by penile shortening has a promotional effect, but for the penis has been fully developed men, can not achieve the purpose of penis enlargement. Generally speaking, any drug or food can not make the size of the developed penis increase, under normal circumstances, the end of puberty after the development of the penis has also matured, and the size of the penis of a normal person is generally proportional to the size of the body is also related to the erection can be reached after 12 to 18 centimeters is normal. It is recommended that patients consult a professional doctor to improve the state of the penis in sexual life through scientific means, so as to avoid being deceived and causing adverse effects.