What does it mean to "be a man"?
Is it facial hair, an obsession with meat, bulging muscles, or so many sexual conquests
that you can't even remember your partners' names?
And most of those symbols of manliness get credited, rightfully or not, to testosterone,
one of the major sex hormones.
While folks with ovaries might be more familiar with hormones because they play such a central
role in daily life, men have been obsessed with testosterone for different reasons.
Even since before the discovery of hormones, men knew that some kind of chemical in the
testes was responsible for the male aspect of reproduction.
Basically, whatever the essence of manliness was, we would probably find it in the testes.
Right, even the Ancient Greeks saw the overlap of the testes dropping and the development
of those manly characteristics like facial hair, muscles, and sex drive.
There was even a shortlived myth that Testicles, the god of puberty vaporized olive oil and
blew it into the Athenian wind which triggered the testes to grow.
I'm totally joking, Testicles isn't made up.
But the Ancients did see that men who, for whatever reason, had their testicles removed,
didn't fit the role for traditional masculinity.
Higher voices, no beards, and the whole inability to make a baby thing.
Then fast forward a couple years past the "we knew zero things about nothing" stage
of anatomy up to the mid 1800s.
We got that wild testicle transplant thing from Berthold back from the rooster video
which is linked here.
But quick summary, a scientist saw that completely chopping off testicles from a rooster made
it less aggressive, but chopping the testes off and implanting a different testicle into
their gut let them maintain their aggressiveness.
And like, to me, that's pretty peak weird science, but in 1889, a super well respected
French scientist, Charles-Édouard Brown-Séquard, pretty much replicated the experiment on himself.
Brown-Sequard injected himself with testicle secretions from guinea pigs and noticed some...changes.
He reported being like a young man again.
Everything from increased libido, more energy at night, and even better bowel movements.
Normal poops, not just a young man's game!
And if you're thinking this is way too unscientific, you're totally right.
Yeah… he used way too low of a concentration to have any effect on his biology but even
back then, men had this strong mental picture of the testes containing something essentially
manly.
Now, this was back over 120 years ago, and as obsessed as we've always been with buffing
up our manliness, we'd dive way deep into that obsession over the next few decades.
Like we saw earlier in this series, hormones were properly discovered in the early 1900s
and research took off after that.
And because patriarchy, a lot of the trials and experiments were done on men by men.
We're going to see a common theme in a lot of these testosterone studies: this hormone
affects behavior.
Specifically, sexual drive, or libido.
But one of the weirdest practices, came from Eugen Steinach, an Austrian physiologist.
To give him some credit, he did learn a lot about the cells lining the sperm duct - Leydig
cells - and how they produce testosterone.
He was nominated for a bunch of Nobel Prizes too.
This dude wasn't a quack.
And he was doing experimentation on hormones at a time when everything was so new.
Like, in 1912, just a few years after Bayliss and Starling, he implanted guinea pig testes
into female and castrated male guinea pigs and saw them develop more aggressive, typical
male sexual behavior.
Not that it was a new idea, but now we had a growing body of research to show that something
in the testicles was responsible for aspects of sexuality — which is a broad idea.
Steinach decided to apply this idea to humans.
Which is where it got weird.
He developed a surgery called a "Steinach vasoligature".
Vaso- meaning vessel, ligature meaning "tie off".
I'll give you a second to guess which vessel we're tying off here.
Not a blood vessel — a sperm vessel.
Yep, Steinach was attempting to revamp men's sex lives by performing vasectomies, a procedure
where the doctor snips or ties off the vas deferins, the tube that carries sperm from
the testes to the urethra.
It had been a pretty common male sterilization surgery since way before Steinach.
He thought that by doing a unilateral vasectomy, or only cutting one vasdeferins instead of
both, the body would compensate by producing more testosterone and make the man feel younger
and sexier again.
And while plenty of people were like "yeah, we're pretty sure that doesn't work",
plenty of men still got the procedure.
Which, if you base a scientist's success off of the number of willing participants
and not like, accuracy, makes this dude a genius
Luckily, the 1920s and 30s gave us some actual good science.
Like Fred Koch who isolated the hormone from a bull testicle, which, if you've been to
a county fair before, you know are not lacking testosterone.
Couple years later in 1935, Ernst Lacquer finally extracted pure testosterone and named
it after, you guessed it, the testes.
This was around the same time scientists isolated estrogen as well, so we were starting to get
the idea of how similar they were chemically.
If you remember back in the estrogen episode, the sex hormones are just fancy cholesterol.
Testosterone is produced mostly in the testes by those Leydig cells, and in some amount
by the adrenal cortex.
The /brain/ can also synthesize Testosterone from cholesterol, and it can be converted
from progesterone.
And don't forget, the ovaries can produce testosterone too.
This isn't just a male hormone.
Researchers did wonder why testosterone production slows down after age 30, and it was mostly
due to those cells in the testes and less production of our old friend gonadotropin
releasing hormone.
And that decline over time, usually about 1% percent per year, might be a measure of
overall health as opposed to a function of age itself.
Regardless, men tend to produce less as time goes on.
So quick historical lens check, 1945, rolls around and the hormone marketing starts to
take off.
A guy named Paul De Kruif releases a super popular book called The male hormone claiming
"manhood is chemical, manhood is testosterone".
Even the cover reads:
"The male hormone discloses magic for beyond the merely sexual.
It boosts muscle power.
It banishes mental fatigue.
It eases heart pain.
It even restores the sanity of men in middle life who suffer from physical deficiencies"
And remember where family planning was heading back then.
De Kruif's audience was the men who would father the baby boomer generation.
But the science wasn't exactly legit.
These claims were implied from hormone injections on the "testicularly impaired", a way
of referring to people with testicular injuries or something else keeping them from producing
normal levels of testosterone.
The biggest improvement in sex drive and muscle mass came when someone with very low testosterone
got up into the low-normal range.
But there's a big difference between adding hormones to fix a deficiency and adding hormones
as some kind of performance enhancer.
Remember, your endocrine system is built on feedback loops.
It wants to maintain homeostasis - a nice middle ground.
If it gets out of that sweet spot, it needs to compensate somehow.
Like, if you were a professional athlete and already lifting weights and producing lots
of testosterone, anything on top of that would be way overkill and lead to some gnarly side
effects.
Luckily, we'd never do that….
ohh, ohh…..
Of course, we totally did do that in the form of anabolic steroids.
Anabolic just means to build up, and these injections of synthetic testosterone were
meant to make muscles grow.
When the steroid gets into your bloodstream, it binds to a androgen receptors on muscle
cells, then interacts with the cell's DNA to stimulate protein synthesis.
Then, the weight lifter or baseball player trains normally, but see way bigger results.
But remember, your body wants a predictable, just right level of hormones, so the side
effects like shrunken testicles, acne, or male breast development called gynecomastia
can be attributed to messed up hormone levels.
This also means lower natural testosterone production and sperm count once you come off
steroids.
And you shut down your hypothalamic-pituitary-gonadal, or HPG axis which also messes up luteinizing
and follicle stimulating hormones.
Prescription steroids can be good news for the people who need them, but chances are,
you're probably not one of them.
But that didn't stop men from wanting them, especially when testosterone became available
direct to consumer.
Plenty of people are spooked by injections, but everyone can put a gel on themselves.
So in the year 2000, testosterone gels like Androgel hit the market.
A couple things:
If you watch day time tv or sports commentary, you're guaranteed to see a commercial with
50 something year old man with salt and pepper hair throw a football then climb in a truck
with his wife by his side, and you're like, yeah, they're totally gonna… ya know.
Of course, it implies that any of these treatments will fundamentally change your sex life because
the magic of Testosterone.
So that's one thing, marketing.
The other thing took advantage of another male behavior.
Men are super resistant to going to the doctor, and /way less/ likely to talk about reproductive
health than women.
Like for real, this is a studied public health phenomenon.
Knowing that, product marketing had to expand past the doctor's office.
A drug company called Organon went as far as hiring a doctor to write a questionnaire
called the ADAM survey for men to find out for themselves if testosterone therapy would
be right for them.
Hey, pro-tip, if a drug company comes out with a survey with a way too fitting acronym,
it's probably gonna end up with money in their pockets.
So now you could say, look doc, I think might have low testosterone, or "Low T" as the
disease got rebranded.
How do you rebrand a disease?!
But that's another problem.
What counts as "low" testosterone?
As we saw, hormone replacement therapies really only did some good when the patient was very
low, so that steady 1% per year probably doesn't put you in that category.
With all of the marketing mess ups, you'd think we'd know more about testosterone.
But there's a lot that we don't know.
Like we still aren't certain on the long term effects of testosterone therapy on heart
disease.
According to a 2018 review, low blood testosterone looks like it's associated with higher risk
of cardiovascular disease and overall mortality in certain populations, but not in men that
naturally produce less testosterone.
So is that just because old men tend to have low T and old men tend to die?
Well, a separate 2018 review suggested that testosterone replacement therapy puts users
at more risk of cardiovascular disease.
Full disclosure, there are some conflicting results on this one.
But they tend to back up an FDA recommendation from 2015 saying that these treatments should
be reserved for when the patient really needs them.
If we're so unsure of the risks, should men be pushing it for it so hard?
I'm gonna encourage you to not look at physiology here for a second, but to imagine this one
complexly.
Throughout this video, we've seen that men are insecure about the status of their manliness.
Like, to the point of dropping serious money to fix what they think is a deficiency.
But if you're watching this and you identify as a man, I want to assure you, you're doing
fine - There's nothing deficient about you.
Like, there are a lot of things we need to fix about masculinity if we want to leave
a better society for our kids.
And one of the first things we need to drop is the idea that our success as men is determined
by the size of our muscles, or our number of sexual partners, or at all determined by
the number on a ruler.
You know what I'm talking about.
If you do something good for someone else, or give wholeheartedly without expecting reward,
or amplify a voice that others have silenced, then you're a hell of a man, and I'm proud
of you.
So to come back to the intro of the episode, what makes a real man?
I don't know.
But I don't think it's /just/ testosterone.
Have fun, be good, and I'll see you in the next video.
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