Put aside those mental images of walnut-varnished torsos and arms as big as legs for a moment. Maybe you’re a muscly alpha male, all square jaw and chest-beating machismo. Perhaps you’re a drainpipe who’s literally allergic to sports. It doesn’t matter. Testosterone defines you as a man either way. And it’s so much more than just bodybuilder juice.

In fact, gym performance is just a small part of testosterone’s role in the body. “It’s the most important male hormone,” says Professor Geoff Hackett, consultant at Heartlands Hospital, professor of sexual medicine at Aston University and spokesperson for the British Society of Sexual Medicine. “It’s dominant in controlling your behaviour, psychology, reproduction and sexual performance.”

In other words, it governs almost every aspect of the everyman. When testosterone is secreted normally, you’re a normal dude, with good energy levels, a level head and a predisposition to a healthy body composition. But when the hormone is in short supply, all of that goes to hell in a manbag.

While genetics and lifestyle both hold the purse strings on this hormonal boon, and the former is indeed a lottery, understanding the latter can ensure a steady income now and later in life.

So, to that end, let’s keep you T total.

What Is Testosterone?

The short answer: it’s the endocrinological MVP and without it your whole hormonal team is screwed. “It’s not just for fertility,” says Dr Channa Jayasena, clinical senior lecturer and consultant in reproductive endocrinology at Imperial College London. “It’s important for energy, libido, wellbeing, muscle strength and for making bones thick and strong.”

But it’s important to make a distinction here because testosterone is poorly understood and subject to the worst kinds of bro science. First up, you’re statistically more likely to go about your life with normal testosterone levels than have either a deficiency or surplus. Age related decline is par for the course – “We start to lose testosterone steadily from the age of 40,” explains Dr Jayasena – and lagging T isn’t, as some red tops would have you believe, the male equivalent of the menopause and something to be remedied. It’s a fact of life unlikely to have any drastic effects.

It’s when something causes a dramatic drop in testosterone that you need help. And in this, age has no bearing except in the ease of treatment. But as a general rule, the younger you are, the easier it is to fix.

Your body needs it in a myriad of ways.

The Effects Of Testosterone On Men

1. Body Builder

Testosterone forms the foundation for how you feel at any given moment, while also providing the building blocks for how much of you there is – literally your physical density as a mammal, in bone and muscle tissue. It’s for that reason that your T levels are a key factor in strength and fitness.

But don’t be fooled into thinking more testosterone is always a good thing. Dr Jayasena often treats erstwhile bodybuilders whose dalliances with extreme testosterone supplementation have deflated their testicles, leaving them at best struggling to produce enough of the hormone naturally, at worst infertile and with a host of health problems.

Even the more civilian gym-goer’s understanding of testosterone needs a closer look. As Alex Hutchinson, author of Which Comes First Cardio Or Weights, explains, “Hormone levels don’t predict muscle or strength gains following weight training. Our understanding of the role of various hormones is actually very limited.” So testosterone is important to body composition, but trying to manipulate it at the squat rack is a fool’s game.

You can't manipulate your testosterone levels in the gym

2. Sex Driver

One muscle relies more heavily on testosterone than any other, and it’s an important one. Your hormones hold your penis as if by a puppet string. While trying to understand the roles biochemistry and psychology play in virility is enough to put you to bed with a sore head, one fact stands with rigid certainty: without healthy testosterone levels, you’ll likely suffer erectile dysfunction.

“While many of the symptoms associated with low testosterone can be due to something else – like diabetes or depression – erectile dysfunction and the loss of morning erections is a good indicator that testosterone is the reason,” says Dr Jayasena. But it’s not just hampering your dreams of bedroom acrobatics in the physical sense.

“There can be a loss of libido and general interest in sex,” says Professor Hacket. “Later down the line this can even lead to a marriage breakdown and a man losing his wife and children.”

Low T levels can cause a lower sex drive and erectile dysfunction

3. Health Giver

Things get more complicated when it comes to figuring out the causes of low T and how that might affect your health. Testosterone and insulin walk hand in hand. There’s also a symbiotic relationship between the hormone and the neurotransmitters that govern your mood and sense of wellbeing. That’s why understanding whether low testosterone is causing diabetes, or diabetes is causing low testosterone, is tricky. The same goes for why depressed people may suffer hormonal damage, and people with hormonal problems may suffer depression.

“There are common associations and one leads to the other,” says Professor Hackett. “Low testosterone gives you three times the risk of developing type-2 diabetes; if you have type-2 diabetes, you have a much higher risk of low testosterone.” This chicken and egg scenario doesn’t exactly make fingering the underlying cause easy. The response? “We treat all symptoms,” says Professor Hackett.

There has been a degree of controversy surrounding treatments for testosterone deficiency, mainly coming from loud but unfounded noises from critics who claim T supplementation can increase your risk of things like cardiovascular disease and prostate cancer. Online hysteria abounds, but it’s all recently been debunked by international expert consensus.

The claims are there. The evidence isn’t. If you have low testosterone, the risks of not being treated largely outweigh any supposed risks of hormonal therapy.

It's important to treat low testosterone levels

How Can You Tell If You Have Low Testosterone?

Look south. “It’s not just difficulty in achieving an erection that’s a sign, but struggling to maintain one as well,” says Dr Jayasena. Then there’s the other tricky telltale signs that can just as easily be symptoms of depression or another illness.

“You’ll have a number of bothersome symptoms,” says Professor Hackett. “Loss of libido, loss of morning erections, erectile dysfunction, then you’ll lose physical strength and muscle mass. You might feel excessively tired and fall asleep in the evenings. You could feel depressed and put on weight. When it goes really bad, your beard might not grow and you could lose hair on your legs and get hot flushes.”

It’s important to be honest with your doctor. In fact, overshare. “Talk about the bedroom,” says Professor Hackett. “Men often avoid this due to embarrassment. And doctors are often quick to think depression is the cause without checking for testosterone.”

Talking about sex drive and erections will ensure that hormonal tests are on the table. This is particularly important because antidepressants can actually exacerbate testosterone problems due to their effects on neurotransmitters.

Speaking of drugs…

Should You Supplement Testosterone?

The answer is obvious but it bears mentioning anyway: if you have a deficiency, yes; if you don’t, then most certainly not. Fortunately, as scary as a deficiency sounds, the treatments generally have great success.

“When you raise the testosterone, symptoms improve in variable stages,” says Professor Hackett. “Libido improves quickly; energy and erections may take a bit longer. Then losing weight and improving insulin resistance might take 12 months.

But by improving all those symptoms you’ll motivate a guy to do something about his life, and [potentially] save him losing his wife and family. It’s a package of care.”

The best treatment for you will depend on your lifestyle. They mainly vary on how regularly they need to be administered. Someone with a good morning routine, for instance, would benefit from regular low-dose gels applied in the morning. For others, an injection that delivers testosterone over a longer period might work best. Professor Hackett recommends being honest with your doctor about your lifestyle to ascertain the best route for your body.

How To Increase Your Testosterone Naturally

One thing needs to be made clear here and painfully so: it’s statistically unlikely you need to increase your testosterone and to do so unnaturally could be devastating to your health. That said, maintaining healthy levels is, as government bodies are so wont to tell you about almost every aspect of health, predominantly a case of living sensibly.

1. Find Your Balance

What does a healthy lifestyle actually mean in terms of testosterone? It’s perhaps best summed up by a recent study by Australian scientists. “This was a big study,” says Dr Jayasena. “It graded men according to their lifestyle. The better they did, the less chance they had of testosterone deficiency. Never having salt was worth a point. As was regularly eating oily fish, doing moderate exercise, having a healthy BMI and not smoking or drinking. All sensible stuff.”

Living a healthy lifestyle will help boost testosterone levels

2. Dodge The Drugs

Drugs, medicinal and otherwise, can wreak havoc inside your body. “Painkillers can interfere with neurotransmitters and the pituitary gland, which controls hormones,” says Professor Hackett. “Recreational drugs, like cannabis, LSD and cocaine – drugs that alter your brain chemistry – will affect some fairly critical neurotransmitters as well.” Unless you’re being prescribed something you need, don’t do drugs, kids.

Recreational drugs can lower your testosterone levels

Pop The Right Pills

Conversely, certain anti-inflammatory and anti-anxiety supplements, which have a positive effect on neurotransmitters, can help keep things more balanced. Fish oil and vitamin D supplements have been found to have the most efficacy. Remember, this is about prevention, not cure.

Fish oils can help increase T levels

4. Burn Some Blubber

It’s not just obesity but also the hidden, visceral fat – the stuff around your organs – that can cause a dip in T levels. “At Imperial College, we’re looking closely at the effects of targeted weight loss for men with fertility problems,” says Dr Jayasena.

“Obesity is the big enemy but visceral fat is as well. Five-to-10 per cent weight loss could be enough to turn this around. Men need to help themselves as much as look to doctors.” You heard the man – get on your bike.

Exercise is good for your testosterone levels

5. Eat Yourself Healthy

When it comes to testosterone, food is fuel. “All hormones rely upon processing for manufacturers. That means you have to have the raw materials for them and the cofactors that make them,” says nutrition consultant and the author of The Dodo Diet, Drew Price.

“Fats are often highlighted as necessary for T production, but in reality most people eat more than enough. Evidence suggests that low intakes of carbs can also impair production as well as the downstream processing and utilisation of T. But one factor that really inhibits hormone function is insufficient calories.” In other words, eat like a man.

A healthy diet will help increase testosterone levels

6. Lose Some Booze

Going teetotal will help ensure you stay T total. But even just being sensible with your alcohol consumption will be beneficial. “Booze is obviously a T killer,” says Price. “Interestingly, it will raise hormones associated with T production in the short term but run down total production in the long run. It also reduces sleep quality, a deficiency of which is a one-two punch resulting in less muscle, less virility and more fat.”

Alcohol can dramatically lower testosterone levels

7. Spice Things Up

A parting tip: stock up on chillies. “There’s some evidence that suggests spicy foods may increase testosterone. But it also might just be the case that guys with higher testosterone levels prefer spicy foods,” says Price. “It’s not entirely clear.” Even so, there’s no harm in adding some heat to your diet, even on the smallest off chance it might spice things up in the bedroom in the long term.

Spicy foods might boost testosterone levels