“Does testosterone increase penis size?” is one of the most common questions that we’re asked here at Behaveo, and its understandable due to the amount of misinformation about testosterone and also societal standards (driven by unrealistic standards from porn) that men should have a certain size penis.
A big reason why testosterone is still popular as a supplement is because it helps build muscle. That muscle growth has a lot of people wondering what else testosterone can grow, and since testosterone is the primary male sex hormone, many wonder if testosterone increases penis size.
Related reading: Can Hormones Cause Anxiety? »
The answer to the question is a complicated one. There’s no definitive answer, but there have been a few studies showing that yes, testosterone can help increase penis size. In those cases, the mechanism for doing so was not fully known, and the result came as a welcome surprise.
As we’ll visit below, however, this is not the case for everyone.
Please always seek medical advice from your GP by taking supplements like testosterone
What is testosterone exactly?
Testosterone is the hormone that enables healthy sexual reproduction in men. It is the hormone that starts puberty in boys and is also responsible for arousal and many other feelings and reactions in people. Testosterone plays a vital role in puberty, but it continues in meaningful ways throughout a man’s adulthood.
Testosterone enables or regulates many elements of appearance. This is because testosterone is also the driving force behind secondary sexual characteristics. These are things like facial, armpit, and pubic hair, as well as increased muscle and bone mass.
Low levels of testosterone can lead to poor erections or the inability to get them at all. It also causes an inability to grow facial hair and secondary sexual characteristics. Conversely, high levels can lead to irritability and aggressive behavior. Additionally, high levels of testosterone cause acne and oily skin and can worsen sleep apnea for those afflicted.

Testosterone and penis size: the science
There is very little science covering the topic of testosterone and penile growth. There are, however, a few studies–some of which are quite old. These studies mostly deal with Low-T and micropenis reversal through testosterone. While these are successful studies, it is important to note that they are also very specific in terms of use-case.
Low-t reversal
This Men’s Health article goes into detail on this study which shows some interesting results. In it, a 34-year-old man was able to reverse several medical conditions through testosterone injections. When he first presented himself, he indicated that he had scarce body hair. He also had his penis measured and found it to be just above micropenis levels.
Those conducting the study discovered the relationship between his low amounts of body hair and low testosterone levels. As a result, after nine months of treatment, he was able to discontinue injections because all of his symptoms had vanished.
Not only did his body hair grow back, but his penis also grew by over 3 inches. In addition to this, his testicular volume (previously very low) returned to normal levels.
Micropenis reversal
One study, conducted in 1978, found that five patients were able to reverse their micropenis condition. They did this with gonadotropin along with topical testosterone. Gonadotropin is another hormone that acts on the gonads. The average increase in length and width after treatment with topical testosterone was 60% in length and 52% in width.
This comes with a big caveat, however. In the study, they note that the response from “postpubertal male subjects” was “minimal.” meaning that the responses mostly recorded came from subjects still going through puberty.
This leads us to the overall question provided by the science:
Do hormones stabilize or mobilize?
Hormones give us all kinds of signals but their main goal within our body is finding balance. Testosterone is no exception. The reason that the growth was more robust in boys going through puberty is that they had that growth yet to go.
All science points towards penis size being something of a determinate length from birth to the end of puberty. The results provided by the micropenis studies may indicate something other than just growth. It is possible that it only enabled the potential that those individual penises had before an interruption of testosterone. That said, there’s too little information at this point to know if even that is the case.
Testosterone isn’t worthless, however. For those with low testosterone levels, having a supplementary option is a godsend. Hormones are best used for their intended purpose: balance.
Does creatine increase testosterone?
Another question we get asked here, especially with gym-goers, is about creatine. Creatine is a naturally occurring compound in our bodies that helps provide energy for muscles. Because of this, it is often used as a supplement for weightlifters as a way to replenish as they work out.
There is some research showing that extended creatine use combined with exercise may lead to higher testosterone levels. This is likely an indirect result of heavier workouts from the creatine, but the reasoning is still hazy. If it is indirect, it would point to the following flow:
- Creatine provides added energy to muscles
- Muscles used in heavier workout
- Testosterone levels increased from physical exercise
That said, the testosterone change may be more straightforward than that. Like the rest of the article, we simply do not have enough information yet.
FAQs on testosterone and penis size
Does testosterone increase penis size?
While testosterone plays a crucial role in male sexual development, there is no clear evidence to suggest that it directly increases penis size beyond its normal growth during puberty.
Can low testosterone levels affect penis size?
Low testosterone levels during puberty can result in a smaller penis size than what is considered normal, but this is typically only a concern for those with very low testosterone levels. For most men, testosterone levels do not significantly impact penis size once growth during puberty is complete.
Are there other factors that can impact penis size?
Yes, genetics and lifestyle factors such as obesity, smoking, and poor cardiovascular health can all impact penis size. However, these factors are not directly related to testosterone levels.
Can testosterone therapy increase penis size?
Testosterone therapy can be used to treat low testosterone levels, but there is no evidence to suggest that it can increase penis size beyond its normal growth during puberty. In fact, excessive testosterone therapy can even lead to shrinkage of the testicles and penis.
Is there anything I can do to increase penis size?
There are no proven ‘safe and natural’ methods to permanently increase penis size beyond its normal growth during puberty. Some products and procedures claim to increase penis size, but they are typically not supported by scientific evidence and can even be dangerous. Accepting and being comfortable with your natural penis size is important for overall sexual and mental health.