What should I do if I’m 21 and my penis is as small as a child’s?

Penis size varies from person to person and is generally related to the individual’s constitution, physical development and other reasons. The size of the adult penis varies from 4.5 to 8.5 cm when flaccid to 9 to 16 cm when erect, and is considered normal as long as it is within the range. There is no direct relationship between the length and size of the penis and sexual ability.
If the patient’s penis length and size in line with the above standards is normal, do not have to worry too much, usually should pay attention to diet, eat more high-protein nutritious food, eat more fresh vegetables and fruits, appropriate amount of vitamin supplementation, regular work and rest, do not stay up late, and more to strengthen the exercise.
If the patient’s penis length and size does not meet the above standards but usually there is no abnormality, there is no erectile dysfunction, sexual life disorders and other problems, you can continue to observe, supplement nutrition, and actively exercise.
If the patient’s penis length does not meet the standard and there are erectile dysfunction, sexual life disorders and other problems should be timely medical treatment, accept the relevant examination, clarify the cause of the disease, symptomatic treatment, so as not to affect the normal life or even infertility.