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Penis Size


At some point, most young men will wonder how the size of their penis compares to other guys. Asking this question is a normal part of development, especially if your body is going through some of the normal changes associated with puberty or if you are considering becoming sexually active. Maybe you first asked how you "measured up" when you showered with your teammates in a locker room or if you saw your older brother naked. Wherever or whenever it was, this guide will help to answer some of the questions most young men are asking themselves about their penis size.


Is there a normal penis size?

Bodies come in all different shapes and sizes - that's partly what makes each of us special and different from each other. It's important to understand that the size of a guy's penis is determined by genetic traits that he inherits from his parents - just like we inherit our height, eye color, and skin tone. The studies that have been conducted list the average adult penis size between 5 and 6 inches when fully erect, as measured from the lowest portion of the stomach, just above the base of the penis, to the tip of the penis.


Comparing yourself to other guys may lead you to believe that your penis is different in size. However, it's important to keep in mind that we all develop on different schedules. You may look different from that guy in the locker room who is three years older than you. Even guys the same age can develop more quickly or slowly. Be patient - late bloomers will eventually catch up to the rest of the pack. Most guys are fully developed between the ages of 18 and 21.


When will my penis start to grow in size?

When guys hit puberty, a number of changes occur in the body including increased hair growth on certain parts of the body (chest, pubic area, legs, underarms) and a deepening of the voice. Puberty will also be marked by an increase in the size of a young man's testicles, followed by growth in the size of the penis. The penis typically reaches its final size 4 to 6 years after the testicles enlarge. On average, young men will experience the most rapid growth of their penis and testicles between the ages of 12-16 years.


Can I change the size of my penis?

Despite the claims of countless products, exercise techniques and herbal remedies on the market, none of these will increase the size of your penis. Remember that even natural or herbal substances can cause bad side effects, especially when taken in high doses. Be sure to consult your health care provider if you're considering taking one of these substances. Medicines such as Viagra, which allow men with erectile dysfunction to maintain an erection, do not increase the size of a young man's penis and can be extremely dangerous to take without a prescription from a health care provider.


What should I do if I think my penis is too small?

The vast majority of men are born with a properly functioning penis that will allow them to urinate and engage in sexual activities without a problem. If you're having serious worries about the size of your penis or you're late going through puberty, speak with your health care provider who can provide you with guidance.


Additional Resources:


Growth and development of male external genitalia: a cross-sectional study of 6200 males aged 0 to 19 years. Tomova A, Deepinder F, Robeva R, Lalabonova H, Kumanov P, Agarwal A. Arch Pediatr Adolesc Med. 2010;164(12):1152.


If you're concerned about penis size, here's a tip on how to bring it up with your provider: "What's the normal size penis for someone my age?".


Written by the Young Men's Health Staff at Boston Children's Hospital


Updated: 10/15/2014


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