Testosterone has an image problem.

To some people, high levels of the primary male sex hormone is a synonym for aggressive or toxic behaviour, or the sinister goal of doped-up Olympians and steroid-fuelled bodybuilders. To others, a low level of testosterone is the cause of every male health problem from dwindling libido to midlife lethargy, to increased risk of obesity, diabetes and cardiovascular disease.

Testosterone is somehow both the cause of, and the solution to, all men’s issues: a poison pill and a magic bullet rolled into one. Poorly monitored by NHS doctors but over-prescribed by private clinics keen to offer testosterone replacement therapy (TRT), it can be hard to identify through symptoms alone but easy to attack in our culture war climate. Many believe testosterone is in urgent need of rehabilitation.

“There’s a lot of politics here because of the perception that testosterone is something to do with bodybuilding,” says Dr Geoffrey Hackett, consultant in urology at Spire Little Aston Hospital. “As soon as you mention it, the first picture that somebody gets is of somebody like Arnold Schwarzenegger. And that’s what we’ve got to lose.”

Dr Richard Quinton, consultant endocrinologist at Newcastle Hospitals Trust, agrees that testosterone is misunderstood. “The idea that testosterone is linked to aggression, we have no idea where this has come from,” he says. “And it is not just out there in the lay field, but also in the medical field.”

What men need is clarity, so let’s get back to basics. Testosterone is the primary sex hormone in males, and it is critical for men’s health. During foetal development, testosterone triggers the development of the penis. During puberty, the hormone – which is synthesised in the testes and regulated by the hypothalamus and anterior pituitary – sparks key changes such as muscle growth, bone development and facial hair. And throughout adulthood it supports everything from sperm production and libido to red blood cell creation, muscle strength, cognitive function and energy levels.

It is no surprise, therefore, that low testosterone (‘low T’) is linked to worrying health issues, from erectile dysfunction and infertility to high cholesterol, diabetes, anaemia, osteoporosis and heart disease. In fact, low T is associated with a 35% to 40% higher risk of premature death.

A terminal decline in testosterone?

When news broke about a huge drop in men’s T levels, the concern was understandable. One study discovered a “substantial” population-level drop in men’s T levels between 1987 and 2004, at a rate of about 1% each year. Some research suggests this is even the case among younger men. The headlines were brutal: “You’re Not the Man Your Father Was.”

Explanations range from the impact of testosterone-wrecking everyday chemicals such as pesticides and phthalates, to rising rates of obesity, and the decline in testosterone-boosting manual labour.

But not everyone is convinced. Other research, which compared data from 1988-2004, found “no evidence” of a population-wide decline. Some experts believe any dip is just down to the parallel surge in obesity, or the result of our ageing population: after the age of 40, T levels can drop, gently, by 1% per year, with no harm to a man’s wellbeing.  

The result of all this confusion is chaos. Many men with low T are not addressing it, through a fear of feeling emasculated or a lack of awareness, or they are not diagnosed due to a lack of specialist knowledge among doctors. This leaves them predisposed to anaemia, osteoporosis, depression, sexual dysfunction and other health issues.

But due to aggressive marketing and internet misinformation, there has also been an “epidemic” of T prescriptions for men with normal T levels who are striving for a more muscular physique or extra midlife mojo. The UK has witnessed a huge 90% increase in T prescriptions. But unnecessary treatment, which hampers natural T production and risks supraphysiological (above normal) levels of T, has horrific results, from infertility and shrunken testicles to heart problems. “That’s a road to ruin,” warns Professor Richard Sharpe, of the MRC Centre For Reproductive Health at The University of Edinburgh. “If you (wrongly) start taking exogenous testosterone, that suppresses your endogenous which means that your sperm production process will suffer.”

Dr Channa Jayasena, a specialist in reproductive endocrinology at Imperial College London, thinks T is being overused, underused and inappropriately used. “This is a major challenge in the field: trying to treat the right people who will benefit and make sure we’re not treating people who won’t.”  

Testing for low testosterone

Amid all this chaos, it is the responsibility of men to educate themselves. So what does ‘low T’ really mean? Low T (also known as testosterone deficiency or hypogonadism) is a medical issue in which the testes fail to produce enough testosterone. It can be caused by genetic conditions, injuries, obesity, diabetes, medication such as opiate painkillers, antidepressants or corticosteroids, exposure to chemicals, hormonal disorders or diseases.

Low T is diagnosed through a combination of blood tests and symptoms. In terms of the blood tests, a ‘normal’ T level ranges from around 8-10nmol/L (nanomoles per litre) of blood to 30-31nmol/L. Based on NHS guidelines, a reading below 8 may require treatment, typically through testosterone injections or gels. A reading of 9-12 is borderline: some men might suffer symptoms; others will be just fine. In this grey area, it is not known if treatment is necessary, or will effectively improve symptoms. For example, research suggests testosterone treatment improves sexual symptoms in men with low T levels below 8, but not necessarily in men with slightly higher levels. But if symptoms are present, further investigation would be beneficial.

In terms of which symptoms to look out for, this is where things get tricky. Many symptoms of low T – such as fatigue or depression – are shared with countless other health problems. This makes low T hard to diagnose – and easy to miss. However, research from the European Male Aging Study (EMAS) has demonstrated that it’s the sexual symptoms which are usually most instructive. “Erectile dysfunction, low libido and lack of morning and evening erections are the big three,” says Dr Hackett. Men with those symptoms may not have low T. And men with other symptoms could have low T. But those three are the most reliable indicators.

However, it takes both blood tests and symptoms to trigger a diagnosis. “If a test result is below 8, it’s likely that you will feel ill and benefit from treatment,” says Professor Jayasena. “But many healthy men in their 20s have a testosterone of 9, 10 or 11. And it may be normal for them. And it would be a mistake to treat them, in my opinion, because they feel well. So you need a combination of low testosterone and symptoms.”

This is a key distinction: “lower-level” testosterone is not the same as “low” testosterone. Most endocrinologists adhere to the ‘enough is enough’ theory: if your T is within the normal range, variation within this range doesn’t matter. You might not get symptoms, and treatment won’t necessarily help – and could negatively affect – your health. This is why leading organisations such as the Endocrine Society and the British Society For Sexual Medicine do not recommend population-wide screening for low T. Statistically ‘lower’ test results may also convince men they have problems when they don’t.

The falling T trend

But now we know what ‘low T’ really means, the big question is: how many men are actually affected?

The EMAS data suggests 2.1% of men suffer from low T. But the age breakdown is more instructive. Among men aged 40-49, 0.1% are affected, rising to 0.6% of men aged 50-59, 3.2% of men aged 60-69, and 5.1% of men aged 70-79. So if you are 49 or younger, you have a 1 in 1,000 chance of low T. Even if you’re older, the odds are in your favour. “About 2-3% of older men lose testosterone production, but the majority maintains it,” insists Dr Quinton.

But what about those scary studies about testosterone dropping? “Yes, it is declining,” says Dr Hackett. But this is not an independent trend. “Obesity is one (cause). The increase in diabetes. The increase in drugs that lower it: opiate prescribing, SSRIs (antidepressants), antipsychotics and also phthalates that are supposed to be an important issue in certain countries. Also, if we’re living longer, then we’ve got longer with age-related testosterone decline.”

The wider EMAS data suggests around 20% of men may have sub-optimal T levels (though not low enough to require treatment), but this appears to be closely tied to poor health. “EMAS showed that the people in whom it declines the most are the people on the most medications, who experienced the most illness, who are the least fit, or who have obesity,” says Dr Jayasena.

One study found that every one-point increase in a man’s BMI is associated with a 2% decrease in T. A fascinating study from China added further insights. “The SPECT-China study mirrors the EMAS data into middle age, but when you look at older Chinese men – apart from the 2-3% I mentioned – they have testosterone levels similar to the younger Chinese men,” says Dr Quinton. “So it seems to be a generational thing. Older Chinese men never got into Western diets, they carried on doing exercise, they worked hard, they never got obese… So we think about it as inevitable, but it’s not necessarily so.”

This doesn’t mean that your T levels will – or should – remain sky-high as you age. Even healthy men will face a gentle decline, with no negative effects. But a drop below the medical norms is not okay. “It’s not natural to have the same testosterone when you’re 80 as when you’re 18,” cautions Dr Jayasena. “But it is natural to have aged.”

The term ‘male menopause’ is sometimes used but this is unhelpful. All women experience the menopause, which involves a rapid decline in hormone levels. But the majority of men don’t suffer from low T, and most changes are glacially slow. “There’s no such thing as the male menopause,” insists Dr Hackett.

In fact, an age-related dip in T may be welcome as men mellow into their senior years. For example, research suggests new fathers experience a dip in T – a possible evolutionary adaptation as they switch to a more caring and calmer parental role. As Ashley Grossman, professor of endocrinology at the University of Oxford, commented: “Biology may be much more subtle and adaptable than we had previously thought.”

Ageing and decline testosterone

But bubbling below the surface here is a key philosophical question. How much are men willing to accept getting older? “Where opinions differ is to how much you should accept that, or how much you would want to interfere,” says Professor Sharpe. “In other words, to start medicalising it and offering treatments. I am in the camp of no treatments, apart from (for) individuals who have clearly obvious clinical signs of testosterone androgen deficiency.”

Dr Jayasena agrees: “There may be risks with trying to supplement your testosterone to 18 when you’re 80,” he says. “It’s like saying: I used to play five-a-side football when I was 18, so I should be playing when I’m 80. But you could do other harm to your body.”

NHS guidelines suggest anyone with T levels above 8 shouldn’t need treatment. But for men in those lower ranges – 9-12, even up to 14-15 – specialists still argue over where to draw the line. “When you’ve got an NHS that is struggling to keep going, does the burden have to fall on the public themselves if they want to aspire to something better?” asks Dr Hackett. “And this is a fundamental question that we have got to come to grips with. Because if you look at the fact that the three major symptoms of low testosterone are erectile dysfunction, loss of morning erections and loss of libido, some would say, well, the planet is not going to self-destruct if these things fall with age.”

However, Dr Hackett points to a paper by Dr Michael Zitzmann which showed that as T levels slide lower, more serious symptoms can develop. Below 15, you might get a slight drop in vigour or libido. You might not. But below 10 is linked to a higher risk of diabetes. “If you’re talking about below about 15, you’re getting a bit of lack of enjoyment of life, and your mojo might have gone a bit, well, if somebody talks to a GP like that, the GP’s mojo probably went 10 years ago, so he’s not sympathetic to this guy who says: ‘When I run a marathon, I’m getting more tired in the last five miles.’ He’s switched off and he is looking out the window. And if you were the person at NHS England setting the level for treatment, would your priority be to switch on middle-aged men’s mojos? No, you’d be only interested in the level that you’ve got for preventing diabetes.”

It is possible that the goalposts may shift in years to come, with tests and treatments offered to men with specific health issues. For example, Dr Hackett points to the T4DM study in Australia which showed that men with a T level of 14 or lower who were given T therapy cut their risk of Type 2 diabetes by 40%, compared with lifestyle interventions alone.

But the big message is that most healthy men are highly unlikely to suffer from low T, and anything other than a gradual but harmless age-related decline may well be down to poor health, which is fixable through lifestyle changes. “To some extent, you as a man can minimise the chances of these things happening,” insists Dr Jayasena.

Regular exercise and a healthy body weight are key. One study found that overweight men who lose weight cut their chances of low T by almost 50%. And research suggests resistance training can also raise testosterone levels. “Even in those men who do have falls in testosterone levels, due to ill health or obesity, we know that what puts everything right is if you address the underlying problem,” says Dr Quinton.

Getting on top of testosterone

But what about men who genuinely suffer from medically low T? If you have symptoms, your doctor can order tests. And if low T is identified, treatment is available in the form of testosterone injections or gels. Studies confirm this can improve the symptoms of men with low T relating to sexual drive, erectile function, cholesterol, muscle mass and bone density, hugely changing a man’s quality of life. Whether it improves depressive symptoms or cognitive function is less clear. But this is an important medical treatment.

The real challenge, however, is getting diagnosed. “With some symptoms like fatigue, poor concentration, low mood and feeling sleepy, they could overlap with other things, particularly depression,” says Dr Hackett. If you’re lucky, your doctor will pick up on the issue. But it may be down to men themselves to remain alert to symptoms and to initiate conversations. Dr Jayasena would like men to be able to have an “open conversation” with their doctor. For men with symptoms, tests can diagnose a problem or offer reassurance that all is well. “If people are unwell, and they know what the signs are, it’s perfectly reasonable to access a health check,” he says.

Right now, too many men with low T are slipping through the net. That is why some medical organisations suggest men with certain conditions, such as infertility, diabetes, obesity and unexplained anaemia, should be screened. “Men won’t necessarily complain of sexual dysfunction, but they might turn up in a fertility clinic, or in an osteoporosis clinic with fractures or unexplained anaemia, and most of these men aren’t really getting diagnosed,” says Dr Quinton, who is striving for greater understanding, clarity and research.

The risks of self-diagnosis

With low T often misunderstood in NHS settings, some men choose to self-diagnose or use private clinics. Anyone can order a test online, or from a local pharmacist. But T levels fluctuate wildly based on the time of day (higher in the morning, lower in the afternoon), food intake and sleep quality. That is why doctors arrange two tests, in the morning, after an overnight fast, four weeks apart. “It is really easy to measure a low testosterone level,” warns Dr Quinton. “That can be done by doing a blood test in the afternoon or evening, when you’re unwell, after a big meal, or after a poor night’s sleep.”

No man should seek treatment based on a self-diagnosis or a single test. But doing a test – if you have symptoms and follow correct protocols – may begin the process of self-discovery. You can then speak to a doctor and see what further action may – or may not – be needed.  

Men’s health clinics also offer testing and treatment services. Respectable clinics say they are simply filling the gaps in the NHS, giving neglected men the help they need. It’s a fair point. But less scrupulous outfits market T to healthy men as a way to improve their gym gains or midlife libido. “The motivation, quite understandably, of a private clinic is to make money,” says Dr Hackett. “And the way you make money is not through the consultation. It’s by the long-term provision of product that gives you a profit.” While specialists like Dr Hackett order prescriptions of quality treatment from a pharmacy, many clinics dish out cheap, short-acting products with a high mark-up.

So if you do decide to go private, look closely at the expert’s credentials. “My own view would be to avoid seeing any specialist who doesn’t also do an NHS clinic,” advises Dr Quinton. “If the person you are seeing is pure private sector, and particularly if they’re not a registered endocrinologist, then think twice. Think three times.”

TRT and other solutions

With so much confusion around, men are right to educate themselves, ask questions, and seek information. For men with low T levels, T therapy can offer life-changing results. But for men with healthy T levels, T therapy can do catastrophic harm. Some doctors are afraid that simply talking about T will lead to a flood of men demanding treatment they do not need. Other doctors fear that not talking about it will leave men with low T suffering in silence. Both fears are correct. And the only solution is better education, research and awareness. But one key message shines through the fog: most healthy men will have healthy T levels. “Try and make the most of your own testosterone by looking after your health,” says Professor Sharpe. “For most men, it is largely under your own control.”

Dr Quinton says it is time to end the unreasonable fears and unreasonable aspirations swirling around testosterone. “The unreasonable fears are that testosterone causes everything from prostate cancer to aggression and heart disease… But you also have unreasonable expectations, which is that everyone, no matter what state they are in, or how old they are, should have the highest level of testosterone, and that testosterone is the cure-all. There is enough evidence to disperse all these unreasonable fears and expectations. But it is a matter of getting the message out.”