Testosterone was invented in the 1950s by Winston Churchill but started getting siphoned out of men by electric cars when Hollywood invented soy milk.
Or at least, that’s what I learnt on TikTok.
If life seems flat, you’re running on empty, and work stress is the only thing getting you out of bed in the morning, then your mates, gym buddies and algorithm have probably cited testosterone.
Fatigue is a serious problem that needs to be looked into. It limits what you can get from the world, and what the world can get from you. It can also be a sign of an underlying medical problem, so it’s important to try and figure out what’s going on.
To save yourself money and time, it’s worth knowing how testosterone fits into the picture and the signs you might be low.
What testosterone does in the body
If you thought your book club group chat was complicated and full of drama, wait until you hear about endocrinology.
Hormones are your body’s way of talking to itself, like a biological version of WhatsApp. Testosterone is just one hormone among hundreds that the body uses to send messages from one organ to another.
Within the larger community of your entire body, there are thousands of smaller group chats going on. One of these chats is about sperm production. In here are a dozen or so contacts: the brain, the pituitary gland, the testicles, and a team of hormones.
Your brain can’t just text “My guys, we need ten thousand swimmers by lunchtime” to your testes. Instead, an area of your brain called the hypothalamus secretes a hormone called GnrH (gonadotrophin-releasing hormone, where ‘gonad’ means your testicles, and ‘trophin’ means stimulating) in regular pulses. Here, it’s the pattern and amplitude of the pulse that matters, as if your brain had said “I’ll send you a thumbs-up emoji every 5 seconds to let you know everything’s good here and you should keep doing what you’re doing”.
These pulses of GnrH travel through a specialised blood-vessel system to the pituitary gland, which is a little pea-sized organ at the base of your brain. The pituitary detects the GnrH pulses and releases two more hormones: FSH (follicle-stimulating hormone) and LH (luteinising hormone), which travel through the bloodstream to the testicles.
There, FSH helps the testicles with the production of sperm, and LH prompts the testicles to make testosterone. Some of this testosterone stays in the testicles, and some gets sent out into the bloodstream. On the way, some of it converts into estradiol, a type of estrogen, which helps to regulate the amount and pattern of GnrH produced by the hypothalamus.
This system is called the HPG (Hypothalamus-Pituitary-Gonadal) axis, and it means the group chat is constantly pinging with contacts reacting to each other’s messages. It’s incredibly complicated, but somehow we’re all still alive.
Because things are constantly happening to your body – like time, food, temperature, stress, sleep, moving, not moving, and interactions with other people – your body always has new things it needs to talk about. This means that hormones, the messaging system of the body, are always changing depending on what’s going on.
Testosterone is in at least a dozen chats like this one, where parts keep each other in check and everyone works together for the common good (which is you).
What are the signs of low testosterone?
Since testosterone fluctuates constantly and always works as part of a close team, ‘low testosterone’ can mean a lot of different things.
It doesn’t just mean ‘not much spare testosterone floating around in your blood’ because that’s only a tiny part of testosterone’s story.
Someone could be packed full of testosterone but their body doesn’t register it for some reason. Someone might have have an unusually small amount of testosterone but their body is super sensitive to it. Someone might have a problem making testosterone, or transporting testosterone around their body, or interpreting the signals of testosterone, but none of these issues are simply ‘low testosterone’.
They involve testosterone, but indicate deeper problems with other parts of the system.
One single testosterone blood test result doesn’t really mean much – it’s like measuring how much your friends like you by testing how many phone notifications you receive in a minute. It’s more complicated than just a single number.
“You wouldn’t usually measure testosterone by itself,” says Chris Muir, an endocrinologist with a particular interest in men’s health and testosterone replacement therapy.
“You would typically want to measure testosterone plus luteinising hormone [and] follicule-stimulating hormone. These are the hormones required to see how the testes and the pituitary gland are communicating with each other. Because if LH and FSH the gonadotrophins are normal, it makes it very unlikely that your testosterone is deficient, irregardless of what the number is,” he explains.
Testosterone is involved with so many parts of the body, that people have to be examined holistically to figure out which part of the hormonal system might be malfunctioning, and why.
“[Low testosterone] would usually present with a lot of very highly specific signs: small testes, gynaecomastia [growing breast tissue], anaemia, osteoporosis, they don’t have to shave any more, no body hair, low libido, erectile dysfunction,” Chris notes.
“If someone’s gone through puberty completely normally, unless they’ve had a particular cancer, pituitary tumour, some severe head injury, a major testicular injury, they will not have testosterone deficiency. It’s very rare for people to develop low testosterone post puberty if there hasn’t been some major event that has rendered them hypogonadal.”
Because its job is to quickly rise and fall when organs need to communicate with each other, testosterone can also be very difficult to measure accurately. Medical doctors never rely on just one blood test to judge testosterone.
“One of the key things is that [testosterone] has to be measured under the right conditions,” says Chris.
“And even if somebody does measure it under the correct conditions and gets a low result, in 30% or 40% of cases, if it’s remeasured … it will [be normal].”
“It’s also important to know that when you’ve measured testosterone on a blood test, it’s [only] an estimation of your testosterone level. It’s not an exact measurement.”
“And if it’s done by immunoassay that [type of testing] has a lot of variability … so it [your real testosterone level] could be plus or minus 10, 15, or 20%. So that’s why just measuring testosterone as a screening test for somebody who has no signs or symptoms of testosterone deficiency is kind of a waste of time.”
“Often in people with obesity and other health issues, they are not testosterone deficient – testosterone only reads low on a blood test because its carrier protein, SHBG, is low due to the effects of insulin resistance and adiposity on the liver. [Low testosterone blood serum levels are] just a lab artefact for most people.”
This means that using testosterone replacement therapy to fix fatigue only masks the true cause. Injecting testosterone is just shooting up the messenger.
‘You can put them on testosterone and increase their testosterone level, but you’re really not getting at the root issue … They haven’t really improved their health. If anything, they’ve possibly made it worse because you’re fighting against what the body wants to do with testosterone.”
Chris also notes that large medical trials have actually been done to see whether testosterone replacement therapy helped people who had slightly low testosterone levels due to age and chronic health conditions.
“[Testosterone replacement therapy] had no significant clinical benefits apart from maybe a minor increase in sexual libido. So it didn’t fix their low energy. It didn’t fix their low concentration, didn’t fix their brain fog. It was over 8000 men. 30% of them dropped out of the trial because they felt like they were getting no benefit.”
What happens if you take TRT anyway?
“When you take testosterone above what your body is designed to handle, you will develop what’s called polycythemia … where your bone marrow will increase red blood cell production, which means your blood is thicker. And then your heart is having to pump that thickened blood around the body,” says Chris.
“In the short term, that may not cause an issue. But [in the long term] you can develop heart failure from the extra work that it takes to pump that thickened blood. And it also puts you at risk of things like blood clots, certain types of cancer, and a whole range of other health issues” he warns.
TRT can give you a short-term boost. Psychologically, it feels good to take control of your body, and since all those extra cells in your blood can carry more oxygen, some people might get more energy. It will also stimulate muscle growth – but you won’t be able to maintain it without becoming dependent on synthetic testosterone.
“You can develop testosterone dependence, even if you’re not using it at that high of a level,” observes Chris.
“When you try to stop testosterone, many men will feel it’s like if you stop smoking. [And] their body’s own testosterone production will have been suppressed for such a long time that it may take months or even years to kick back in.”
Taking synthetic testosterone can stop your body making its own testosterone. Introducing TRT into your body when you don’t really need it is like hiring an over-the-top drag queen to impersonate one of your friends in the group chat. The real friend is just going to go quiet and maybe decide to log off forever.
Aren’t men’s testosterone levels declining worldwide?
“The range of testosterone in healthy people is very, very broad,” says Chris.
“It’s just something that’s a natural part of human variation. And one person is not more or less manly, or physically capable than another [just because of their testosterone level]. When you look at elite athletes, testosterone can range anywhere from 7 to 40 nanomol per litre, and all of these people are competing at a very high level.”
But not all of us are elite athletes. There is something that’s causing widespread health problems and low testosterone – it’s our lives, our jobs, and our stress levels.
“It doesn’t take a lot of excess weight to have an impact on somebody’s testosterone level,” Chris warns.
“Even once the BMI is about 25, [which] generally would be considered close to normal, a man would have a 3 times increased likelihood of having a testosterone level of less than 10, which most people would consider to be low. But that’s reversible with weight loss.”
“[If men have any other health conditions] it can have an impact on their testosterone level, not because it causes any problem with their testes or their underlying ability to produce testosterone, but it suppresses the hormones that come from the pituitary gland or the hypothalamus.”
“That’s a physiological adaptation to reduce their reproductive fitness so that they don’t cause a pregnancy when their health is not optimal.”
As the news is constantly reporting, male fertility and sperm counts have been declining in recent decades. However, sperm are delicate little guys and while they’re part of the same system as testosterone, they’re not the same.
“Testosterone is very important for sperm production, but I think it’s probably a separate thing,” muses Chris.
“[Declining sperm counts] probably does have more to do with, again, obesity, [and] exposures that we have in modern day society [such as] endocrine-disrupting chemicals, things in the food, etc. Sperm is much more susceptible to environmental exposures and toxins than testosterone production.”
What’s really causing your fatigue?
Unfortunately, Chris observes, “most adult working people are fatigued.”
“All of these social media and online sources often promote a very artificially inflated reference range for testosterone that they would consider normal. And the doses of testosterone that they would recommend for replacement are often far above what would be normal replacement doses,” he says.
It’s hard to feel exhausted every day and not know why. Low testosterone can seem like an obvious cause as one of it’s symptoms is low energy and there are lots of people willing to sell you tests.
While your algorithm might point you towards quick fixes, digging deeper might save you literal heartache. Like many areas of life, it’s better to measure twice and cut once, rather than wasting your time and money on false starts.
Finding a supportive GP who is open minded and listens to your problems is a great first stop – though it’s often easier said than done. Look for GPs who say ‘men’s health’ on their profile page or contact the reception and ask. If they don’t have a GP who does, they can often point you to another clinic they know.
While you’re dealing with this challenge, take extra time for yourself. Try to do a little bit of exercise and eat as healthily as you can manage – remembering that mental health is a type of health. Sadly, ‘eat healthy and exercise’ is a classic for a reason. Try to step back from work if you can, and focus on quality sleep and quality people. Finally, recognise that it took a while for you to get into this state, so it’ll take a while to get out of it too.
