An expert debunks the most frequent fallacies regarding testosterone.
The hormone is linked to a wide range of masculine behaviors.
Testosterone. Most people will associate it with the male sex hormone,
a substance critical to men's health and well-being.
While this is essentially right, there are a number of widespread beliefs
regarding testosterone that deviate significantly from scientific reality.
A recent study has cast new light on traditional misconceptions and half-truths regarding the hormone,
including its function in the development of fertility, aggressive behavior, and even strong leadership.
We spoke with Dr. Channa Jayasena, an endocrinologist at Imperial College London, about this and much more.
What exactly is testosterone?
Testosterone is a hormone that acts as a signaling molecule. It is mostly produced in men's testes,
but it can also be produced in smaller amounts in women's ovaries and both men's and women's
adrenal glands.
It whizzes around the body, acting on tissues to accomplish certain tasks. These include influencing
behavior, developing reproductive function, causing bodily changes - such as armpit and facial hair
growth - and allowing boys, in particular, to go through puberty.
Testosterone is a member of a superfamily of hormones known as steroid hormones, which are
fat-soluble
and digested by the liver. Another is estrogen, and all adrenal hormones are steroid hormones.
Are those with higher testosterone levels more aggressive?
No, I'm afraid I can't. In the healthy range of testosterone levels for a man, there is no association
between violence and the male population.
When you move beyond that and into the area of anabolic steroid use, when males take massive
amounts of testosterone that are orders of magnitude higher, you have aggression. But this is
extremely different from the natural effects of testosterone, and I believe this is where some people
get confused.
What exactly is the relationship between testosterone and fertility?
When testosterone is produced in the testes, it is best compared to heat escaping from a large oven.
Your body as a whole experiences very low levels of testosterone, which primarily escape into
the areas around the oven.
The oven, on the other hand, is a testosterone-filled furnace. And those high testosterone levels
are required to bake sperm. When sperm is created, it is half-cooked, and this final phase is
required for spermatogenesis.
It's difficult to describe. However, if you start giving someone testosterone when they don't have it- for
example, if they're taking anabolic steroids - you actually turn off the oven, which can lead
to infertility.
Do elite athletes have naturally higher testosterone levels?
You could believe that if you were born with very low testosterone levels and subsequently
participated in competitive athletics, your performance would suffer just somewhat. But, for the
most part, there isn't. There is no direct, linear relationship between testosterone and physical
performance.
However, there is some controversy about the disparities in physical performance between the sexes, particularly when it comes to those who use masculinizing HRT (hormone replacement treatment).
I don't believe there is an effect among the sexes, but it does contribute to gender variations in
performance.
Some argue that males with high testosterone levels are more successful and make better
leaders and businesses. Is this statement true?
That, I'm afraid, is entirely incorrect. We do know that when men who have a condition, such as
testicular cancer and thus have abnormally low testosterone levels, have their levels increased
back to where everyone else in the population is, they feel more positive, happier and their mood improves. However, if they are currently at or near the average population level, more will not help them anymore.
Can high testosterone levels diminish empathy?
I don't believe there is a link between increased testosterone levels in men and a lack of empathy.
However, we know that males and women have distinct behavioral and psychological distinctions.
Some of these disparities are explained by testosterone influencing cognition in ways we don't
completely comprehend. So, reading into that, I believe this thought is a representation of sex
disparities that we are all aware of.
Dr Channa Jayasena, our expert
Channa is an endocrinologist at Imperial College London's Department of Metabolism, Digestion,
and Reproduction.
His publications in The Journal of Clinical Endocrinology and Metabolism, Current Opinion
in Endocrinology, Diabetes and Obesity, and The World Journal of Urology focus on reproductive
endocrinology.
