Sizing things up

Let’s be honest here – you take one look at those juiced up monsters parading around on the stage at Mr Universe, and it won’t be long before you are wondering;

What effect has all that testosterone had on that dude’s wedding vegetables?

So we grasped the nettle and decided to find out once and for all … “Does testosterone increase penis size?”

The best way to answer that is to quote the Reverend Timothy Lovejoy;


A recent survey suggests that up to 45% of men are worried about the size of their penis.

That means odds are at least some of you reading this are hoping healthy testosterone levels will extend more than just your lifespan and bicep circumference.

In this article we find out if testosterone is really the answer to a bigger penis.

Spoiler Alert: in that respect you are going to be disappointed. Read on to the end though, statistically speak you are probably worrying about nothing.


Let’s start with where we definitely know T plays a role: early development.

Before puberty, girls and boys are pretty much level pegging hormonally in terms of testosterone and estrogen levels. This is why through childhood there’s not typically a great difference in physical size and strength between genders.

After the onset of puberty however, a boy can start producing up to 50 times more testosterone than he was before.

This sudden flood changes us in all the impressive and occasionally mortifying ways you probably remember. Growth spurt, facial hair, deepening voice and of course, penis growth. Between the ages of 12 and 21 your manhood will increase rapidly.

But what if I told you the size it will ultimately reach is determined even earlier still? Way, way earlier in fact.

Want to know about penis size? Talk to your mom. That might sound like the last line said before a particularly nasty bar fight, but actually evidence suggests it’s also scientifically accurate.

Work from the University of Edinburgh in 2009 showed that eventual penis size is determined as early as 8 to 12 weeks into a pregnancy.

It all happens during what the team called the ‘masculine programing window (MPW).’

Experimenting on rats they were able to demonstrate that testosterone is crucial to penis development during this point. The more androgen activity Junior is exposed to during his MPW, the bigger his future.

Lead author Dr Michelle Welsh explains,

“There are two critical phases, both of which are dependent on androgens. Phase one, penis formation, occurs early in fetal life and is the more important phase… Phase 2, penis growth, offers a wider time window for androgen action, anytime from birth to completion of puberty.”

Boys II Men

But what about in adulthood? Will increasing your testosterone naturally increase penis size too? Brace yourselved here guys – in a word, no.

As we’ve seen it’s all to play for in the early stages, but once we’re through puberty, that’s us set for life.

Think of it as nature’s soufflé, lads. The kind of rise you get is dictated by the ingredients which went into the mix during prep. Once it’s in the oven there’s nothing you can do but watch and hope.

Not only will more testosterone later in life not increase penis size, currently nothing else will either.

Any contraptions or pill telling you different doesn’t have a third leg to stand on. The only thing they’re stretching is credibility.

A 1999 study found that treating under developed infants with testosterone enabled them to develop normally into adulthood, but again this is within the crucial MPW.

Flooding yourself with artificial T to try and recreate the puberty effect would be a seriously bad idea.

You risk shutting down your body’s natural testosterone output which can cause serious health complications and loss of sexual function. Negative body changes too, the opposite of what you want.

If your Smokey Robinson looks bigger on steroids, it’s only be because The Miracles have shrunk, if you catch my drift.
Does testosterone increase penis size?

Desperate measures

Importantly, according to the experts hardly any of us have anything to worry about anyway.

In 2015, research by Kings College London, looked at 17 studies which scientifically measured over 15,000 penises and found the average was 5.16 inches or 13.12cm.

“A 16-cm (6.3-inch) erect penis falls into the 95th percentile: Out of 100 men, only five would have a penis larger than 16 cm. Conversely, an erect penis measuring 10 cm (3.94 inches) falls into the 5th percentile: Only five out of 100 men would have a penis smaller than 10 cm.”

So there you have it, if you’re in there, you’re fine. If you’re bigger, bonus.

If you’re not, lucky for you we live in the age of technology, my friend. There’s everything you need out there to style yourself a gigolo version of Inspector Gadget.

It wouldn’t be fair to say T is no help to in this area though.

Apart from keeping you healthy and keeping you full of stamina when you and your John Thomas are at action stations, higher T also breeds confidence. That means fewer needless anxieties, including this one.

So … Does Testosterone Increase Penis Size?

The real answer to this is yes, it does indeed increase penis size. But crucially, not in a way you can harness. It’s too late. For you, that ship sailed long ago.

Even after puberty it has an important role to play in your sex life, but it’s really not about the size of the ship it’s the motion in the ocean.

Testosterone might not make your longboat any longer; but achieving your peak natural testosterone can keep you at full sail and with the energy to keep rowing all night long.

Write a comment

Comment List

  • Sam 26th March 2019

    Hi Rob.
    I’ve recently been diagnosed with Hypogonadism caused by pituitary tumor. My doctor has recommended placing me on TRT which I will be starting any moment from now. Am 34 with a 4″ penis at full erection. I just read somewhere of someone who doubled the size of his penis while on TRT and I will like to know if it’s possible with those of us with incomplete puberty

    • Rob Wright 26th March 2019

      Hi Sam,

      Hmm, interesting question – the crux of it being the ‘incomplete puberty’ part. So I’m guessing you’ve been told by a doctor that you are still undergoing puberty at 34? I imagine that changes the angle slightly, as of course, we are saying in this article that testosterone affects penis size only during puberty.

      I honestly don’t know the answer to that I’m afraid. And I imagine any trials are unlikely to have been done on people in your situation as it’d be too rare to come up with a decent sample size. Honestly – personally if I were you I’d look into it. I’d certainly speak to a doctor about it.

      Just FYI for anyone else reading this who does not have incomplete puberty, adverts for some magic pills claiming to turn you into John Holmes in a month if you just hand over your credit card details are a scam. Avoid!

      Hope this helps a bit, good luck with it.


  • NIGEL 28th April 2019

    I also had hypogonadism but it was weird in my case.. i was not fertil and i had a soft penis 5 inches i think but very small balls like a 13 or 14 year old that just entered puberty. And this was weird cause in erect state i was quite big over 20centimeters (8 inches i think). But i always had medium hard erections and trouble maintaining. I also had manboobs and i would gain (fat)weight Veryy easy and troughout the day my T dropped even further and made my boobs and belly saggy and soft.
    I hated this and lived with it for years cause i was thinking its all because my diet was not ideal.
    Too keep the story short i was given some T and i did not like this cause i measured my T before and it was already above average (weird) and when i was in periods of weighttraining i always saw some quite nice gains when i ate good. I never kept up for longer than 6 months due to interest lost.
    After the T my penis size DID INCREASE by almost an inch when erect(2 centimeters, now around 22CM/8.5inches) and the best thing is my penis even grew in soft state (flaccid?) From 13 centimeters to a Whopping 15.5 centimeters (from 5 to lil over 6 inches) and my balls became much bigger and muchh Harder and more erections.
    Some will say this is very good but in my case its not. I was already big but not rockhard, now i hurt girls more easily even with lube so i gotta constant think about not hurting them, before treatment i did not had this and i also experience that i get mad much faster now and sometimes about small things. I also lost alot hair after this and it is getting even more worse ;( .

    Ps. Sorry for very bad English, im from Amsterdam im not used to writing long storys in English but i still wanted to share my story for you guys.

    • Rob Wright 29th April 2019

      Hi Nigel,

      Thanks a lot for your comment. This page gets a LOT of traffic, I think there are many guys will find it useful. You might even say ‘hopeful’.

      This is the thing, we can quote pubmed clinical studies and statistics until the cows come home but it is important to get real stories from real guys. And don’t worry about your English, it’s way better than my Dutch 🙂

      All the best, good luck with everything,


  • Joe Mama 30th July 2019

    My natural testosterone at 21-years-old was tested and came in at 1100ng/dl — was have severe depression, so they tested everything. Now, you’d think at that level I would be hung like a horse. Well, I am considerably above average at 7.25″, but nothing mind-bogglingly large. What is large is my muscle structure — 18″ biceps.

  • Jorge 25th August 2019

    Looks like laprascopic hernia repair left me with 1″ penis, all head, will testorene supplement help retore? Supposedly, masturbation and exercise to increase blood flow will help.Will vitamins help also?

    • Rob Wright 25th August 2019

      Hi Jorge,

      Sorry to hear that – and sorry to dash your hopes but I’m afraid not. As you’ll see from the article testosterone plays a role in the development (and size) of the penis but only during puberty. Additional test won’t now increase the size of it now unfortunately. I suppose, looking on the bright side at lest you are still operating properly and don’t suffer from erectile dysfunction.

      Best of luck,