Does testosterone increase penis size?

No, testosterone does not increase penis size in adult men. During adolescence, testosterone plays a role in penis growth, but most guys reach full size by their late teens. Taking testosterone replacement therapy (TRT) as an adult won’t restart that growth. Below, we’ll explain more about how testosterone affects penis size.

No, taking testosterone does not make your penis bigger if you’re a fully grown adult. 

Typically, the penis grows in length and width (aka girth) during puberty. But its growth usually ends by the time someone reaches the physical maturity of adulthood. That means taking testosterone as an adult won’t increase penis length or girth. 

Find your starter ED treatment

Get started

How does testosterone affect penis size?

Testosterone plays a key role in penis development and growth, beginning before birth and continuing through puberty. Some testosterone gets converted into dihydrotestosterone (DHT), a powerful male hormone that helps accelerate penis growth. During puberty, surging testosterone levels help the penis and testes grow to their adult size.

But testosterone isn’t the only factor that determines penis size. Research shows that genetics, nutrition, hormones, and environmental factors can all play a role.

If testosterone levels are low before birth or in early infancy due to congenital hypogonadism, this can interfere with normal penis development and may result in a micropenis. But when low testosterone develops after puberty, it doesn’t affect penis size because penile development is already complete.

Testosterone replacement therapy increases testosterone levels in people with hypogonadism (clinically low testosterone) to improve symptoms like low libido. It may also modestly help with erectile dysfunction (ED), fatigue, and muscle loss, though results may vary from person to person. When it comes to penis size, however, the effects of testosterone treatment depend on when it’s given.

For example, studies show testosterone treatment may increase penis size in children with micropenis related to low testosterone, but timing is crucial. Once development is complete, taking TRT as an adult won’t make the penis larger.

It’s important to remember that if your penis functions properly, it’s fine the way it is. Meaning, if you can get and maintain an erection, are able to continue sexual activity to the point of ejaculation, and have a healthy sex drive, you don’t need to worry about penis size.

If you’re still concerned about the size of your penis, keep in mind that many of the products marketed for penis enlargement are not actually going to help. 

Products like penis pumps (vacuum devices that draw blood into the penis) and penile implants are typically used to treat erectile dysfunction. While these treatments can help you get an erection, they aren’t designed to permanently increase penis size. 

Some people elect to undergo cosmetic surgery to increase their penis size. Research on penile enhancement procedures suggest these surgeries come with potential risks and complications, so talk to your healthcare provider about the risks and benefits to determine whether this option is right for you. 

If you have concerns about your penis size or sexual function, it’s important to talk to your healthcare provider to get medical advice. They may want to check your testosterone levels, get a medical history, and maybe perform a physical exam to see if anything is going on medically that can contribute to your symptoms. 

If you have low T levels (confirmed by morning blood tests that have been ordered by your healthcare provider), along with other symptoms (like low libido or excess body fat), your provider may decide to treat you with testosterone replacement therapy — just don’t expect it to impact your penis length or girth.

The normal size of a penis can vary, and a smaller flaccid penis size doesn’t necessarily mean a smaller erect penis. Most men fall in the normal range (somewhere around 5.1 inches in length and 3.4 inches in erect girth, according to one study). While numbers may vary across studies, the general range is what matters.   

If you think your penis is too small, in all likelihood, it’s probably not. However, studies show some prenatal conditions, as well as low testosterone levels in early and infancy and before puberty, can affect adult penis size. 

If hormonal issues interfere with penis development before birth, a child could be born with a micropenis, a rare medical condition occurring in fewer than 1 in 100 people. A micropenis is defined as a stretched penile length 2.5 standard deviations or more below the average for a person’s age. 

Get started

Testosterone plays an important role in penis development, but timing is everything. Taking testosterone as an adult won’t affect penis size because your penis is already developed by the time you reach adulthood. Here’s what we know:

• Testosterone helps drive penis growth as the body develops. Testosterone plays a role in penile development before birth, in early infancy, and before and during puberty, when the penis grows to its adult size.

• TRT won’t increase penis size in fully developed adults. Testosterone treatment may be used to increase penis size in children with low testosterone levels to prevent or treat micropenis, but it won’t make the penis larger once development is complete.

• Low testosterone can affect more than penis size. While penis size is affected by testosterone levels during early development, low testosterone in adulthood can contribute to symptoms such as low libido and ED.

• Most penis sizes fall within normal range. If you’re worried about the size of your penis or symptoms of low testosterone, a healthcare provider can help you figure out whether there’s an underlying medical issue and discuss treatment options.