Men use testosterone for many different reasons throughout their lives. Some, such as athletes and bodybuilders, use it for performance enhancement. Others take it to replace the testosterone their bodies no longer make naturally. In either case, men often have questions regarding testosterone and penis size. Can a lack of testosterone make your penis shrink, and can taking more make it grow?

Natural Growth during Puberty

As you might already know, testosterone is the hormone responsible for triggering pubescent changes in men. It gives men their masculine characteristics and results in the growth of body hair, a deepening of the voice, and, of course, penis growth. Penis size increases dramatically between the ages of 12 and 18, and by age 21, the size of the penis is set in stone. Although some people claim that there are supplements (like testosterone) or even HGH (Human Growth Hormone) that can influence the size of the penis during these crucial years, this is not the case. Genetics determines your penis size and nothing else.

Bodybuilders, Exogenous Testosterone, and Penis Size

A common question among those who are curious about anabolic steroid and exogenous testosterone use is whether these compounds can actually increase penis size. In fact, a few different studies on testosterone supplementation have actually focused on penis growth. Although some growth did occur on average among men who utilized testosterone supplements for performance enhancement, it only totaled about a centimeter, or a third of an inch. It is also important to note that any compound which causes the penis to grow would also affect the testicles and the prostate, which can be dangerous.

Lack of Testosterone and the Shrinking Penis

Many, many men report that they experience penis shrinkage as they age. Much like an abundance of free testosterone can cause insignificant growth, a lack thereof can cause insignificant shrinkage. Studies show that men may lose an average of half an inch over their lifetimes as they age and testosterone production wanes. Although some men report a much greater loss of size, this is often due to the development of abdominal fat and fat in the pubic area which only makes the shaft of the penis appear shorter. As these men lose weight, their penis size returns to normal.

The Real Reason for Increased Penis Size

On the flip side, many bodybuilders and athletes report an increase in penis size as it refers to the girth, or circumference, of the shaft. While a lot of these individuals tend to thank the testosterone or the steroid, believing that the same compound that causes muscle growth must also make their penises grow, this is not the case. The penis becomes erect when the vessels inside become engorged with blood. Since anabolic steroids and testosterone increase blood volume to a degree, the penis’s girth may increase slightly during that time simply because there is more blood inside of those vessels.

To answer the pressing questions, your penis may grow during exogenous testosterone use, and it may shrink if there is not enough testosterone in your body. However, in both cases, the growth or shrinkage is so insignificant that you – and your partner – will never notice the difference.