The average adult male penis is greater than or equal to 2cm in diameter, 6 – 12cm in length in a weak state, and can be doubled to 12 – 24cm in an erect state, but there are significant racial and individual differences. In general, the length of the penis in a weak state is greater than or equal to 4cm, and in an erect state is greater than or equal to 8cm, with a good functional state should be normal. When men are 18 or 19 years old, the size and dimensions of the penis and testicles are generally fixed, and the fantasy of relying on some kind of medicine to achieve a “second development” of the external genitalia is only an unrealistic fantasy. Unless there are endocrine problems, through the appropriate treatment, there will be changes.