Are you tired all the time, with weak erections and stubborn belly fat that won’t shift? This is the reason why… as doctors warn about mistake so many men are making to try to fix the problems

Are you often fatigued? Struggle to sleep? Suffer from aches and pains? Plagued by stubborn belly fat that won’t shift?

These might sound like the inevitable signs of ageing, but if you’re a man over 35, private clinics may have another diagnosis: low testosterone.

Adverts telling ‘tired’ men this could explain their symptoms have been appearing across the London Underground and social media feeds – with influencers offering discounts if you click on an affiliate link for a testosterone blood test at a private clinic.

Based on your results, for around £150 a month, you’ll get your treatment – testosterone jabs – delivered to your door.

One clinic boasts that it has sold more than 200,000 testosterone blood tests in the UK, with around 30,000 men currently on its treatment programme.

However, leading experts argue these clinics are medicalising vague symptoms such as fatigue – that everyone experiences at some point – to sell testosterone replacement therapy (TRT) to men who don’t need it.

And worse, giving otherwise healthy men TRT may affect their fertility and increase their risk of heart disease and stroke.

That’s because testosterone stimulates red blood cell production and if levels are too high, the risk of blood clots increases. Blood pressure and ‘bad’ cholesterol levels can also rise. In the long-term TRT poses a risk to men’s fertility because the brain, detecting testosterone arriving from outside, switches off the signals telling the testes to make testosterone and sperm. With no job left to do, the testes shrink and sperm production falls – sometimes, according to a number of experts, with lasting effects.

It’s not therefore something men should take without good reason, they say. Indeed in this country, TRT is only licensed to treat hypogonadism, where the sex glands produce barely any of the sex hormones, including testosterone.

One expert, Professor Richard Quinton, a consultant endocrinologist at the Royal Victoria Infirmary in Newcastle and senior author of Society for Endocrinology’s testosterone guidelines, said the growing use of TRT via private clinics is ‘the worst instance of medicalising normal biology that I have encountered’.

Indeed as this investigation found, it’s worryingly easy to get hold of TRT based on test results of questionable accuracy. Some private clinics offered me unlicensed drugs and upsold libido boosters with minimal checks.

At 54, I am in the target audience, but there’s nothing to suggest I might have low testosterone: I have no erection problems and no loss of libido – the two key symptoms for prescribing TRT, according to guidelines from the British Society of Sexual Medicine (BSSM).

I regularly exercise and can dance with my kids, aged six and eight, without breaking a sweat: I have an abundance of energy and am the ideal weight for my height.

Yet when I had my testosterone levels checked, I was told I need TRT – despite an NHS check on the same day showing my testosterone levels were so high that my GP gave me further tests to check I didn’t have a tumour in my testicle (thankfully I didn’t).

At the heart of all this is the level at which the private clinics judge whether a man’s testosterone is low. Testosterone blood tests measure both ‘total’ testosterone – i.e. how much there is in the blood – and free testosterone, how much is actually available to use for muscle growth and energy.

On the NHS, TRT is only prescribed after two separate fasting morning blood tests show total testosterone below around 8nmol/L (the BSSM set it at 12), combined with specific symptoms – new erectile dysfunction and loss of morning erections. Fatigue and poor sleep on their own won’t lead to TRT on the NHS.

Under BSSM guidelines, treatment is considered even if your total testosterone is normal but only if you also suffer from severe erectile dysfunction and no morning erections, plus your free testosterone is below 0.22 (again, on the basis of two morning blood tests, more on this later).

However, private clinics are willing to prescribe testosterone at varying levels.

With around 30 UK clinic websites offering testosterone prescriptions, I go on to five of the most prominent providers.

For each I fill in an online questionnaire – then I can order a blood test (usually a fingerprick test). If the test indicates low testosterone, following a second blood test to confirm the results, an online consultation with a doctor can be arranged.

I list my symptoms as low energy, muscle aches and lack of sleep and take my first blood test (for £34) with Voy, which says it’s ‘treated more men for testosterone deficiency than any other UK clinic’.

Under BSSM guidance testosterone blood tests need to be done before 11am and after fasting overnight because levels drop through the day and after eating food, especially carbohydrates.

Yet Voy said I could do the blood test up to 2pm if I was over 40 and I didn’t have to fast (other private clinics suggested the same, on the basis testosterone varies less during the day with age): so I took the blood test at about 11am, after breakfast.

My results, a few days later, put my total testosterone at 17.1 (i.e. normal), but my free testosterone was 0.195 (slightly lower than normal). As my results were ‘low’, I was invited to have a second enhanced blood test (a further £65), which checked 30 blood markers – including liver function and other hormones – to identify whether my low testosterone had an underlying cause.

This time I took the test at 1.45pm after lunch. My total testosterone came back at 16.2 (lower than before); free testosterone was again 0.195.

Voy recommended a video consultation with their doctor. That was the day I had a testosterone blood test with my GP, having fasted overnight that revealed I had a total testosterone of 33.1, not just normal, but high.

At the video consultation, I mentioned vague symptoms such as fatigue and stubborn belly fat – and ‘very occasionally’ difficulty maintaining erections. The doctor prescribed ‘the gold standard’ testosterone treatment – cypionate injections (0.13ml, three times weekly), plus tadalafil (a slow-acting version of Viagra; 5mg daily) for a minimum of three months, at £144 per month.

But my test results weren’t worrying at all, I felt.

‘Whether to treat you is based on the severity of symptoms and not the number – if you indicated that these symptoms [erectile dysfunction] were severe, then it is quite reasonable for them to offer treatment within guidelines,’ says Geoff Hackett, a consultant urologist and author of the BSSM’s guidelines on TRT. Yet I hadn’t said my ‘erectile symptoms’ were severe.

Voy’s doctor noted that my oestradiol – a form of oestrogen, which testosterone is converted into in the body and which TRT pushes higher still – was on the higher side.

Had I started the treatment, my oestradiol could have risen further, potentially causing side-effects such as breast tenderness and enlargement, Professor Quinton tells me – adding that when this happens the usual response is for private clinics to add another drug.

‘Patients get a bit of breast tenderness, so they say, “Well, have some anastrozole or tamoxifen” – both drugs used to treat breast cancer. There’s just a whole raft of one thing leading to another.’

Professor Quinton is also emphatic about the test timing and fasting for a true picture of a man’s testosterone levels.

As for the second test in the afternoon, after lunch – where my levels dropped even further – he is scathing: ‘In my view the second test snared you.’

As for the TRT itself, cypionate is not licensed in the UK so can only be sourced via the clinic on an off-label basis.

Professor Quinton points out that while there are licensed treatments for hypogonadism – Testogel, Nebido and long-acting injections – which cost £40 to £90 for a three-month supply, the type of testosterone often provided by private clinics – testosterone cypionate, which is faster acting – has no fixed price so clinics can set their own (and this can be up to £385 for three months).

‘There is no money to be made out of the licensed formulations,’ adds Professor Hackett. ‘But there’s no evidence that cypionate carries the same safety profile as licensed products. That is one of the BSSM’s major concerns.’

He adds: ‘TRT is a marathon not a sprint. But if you are a commercial clinic, you shoot a dose in, and someone will feel better in five days rather than four weeks on licensed injections – they will be back wanting more.’

Unlike Voy, other clinics I approach – such as Leger, Ted’s Health and Balance My Hormones – all stipulate that blood tests need to be done before 10-11am; Harpal says you can do the test up to 12pm. As for fasting, just one, Balance My Hormones says you need to.

But they will also accept blood tests done at other clinics. So I sent all of them Voy’s results.

This time, however, when I speak to their doctors I say I have no erection or libido problems.

This matters considerably, says Professor Quinton, because if a man explicitly says he does not have these symptoms, then he is a poor candidate for TRT.

Even so, Leger’s doctor offered me testosterone cypionate at a dose of 0.16ml three times a week (£125 per month). The doctor didn’t ask me what time my test was taken.

To its credit, Ted’s Health, concerned that the test had been done so late in the day, did not prescribe me TRT – the doctor described the timing as ‘cheeky’.

But he did offer me a tadalafil prescription, describing it as offering ‘longevity benefits’ as it can lower cardiovascular risk.

The most rigorous consultation was at Balance My Hormones, where a doctor spent considerable time examining my blood results. He said that while my free testosterone was low, my testicles were producing testosterone normally. He also asked the time of the test.

His specific concern was my levels of haematocrit – the proportion of red blood cells that can, if elevated, increase the risk of stroke and blood clots.

My levels – at 46 per cent – were on the high side, which made him cautious, as testosterone raises it directly. (Voy, Harpal and Leger also mentioned my haematocrit, but said it wasn’t anything to worry about. Professor Quinton told me, ‘on testosterone treatment, it would almost certainly become abnormally high’, and therefore risky.)

The Balance My Hormones doctor instead recommended enclomiphene, an unlicensed drug that stimulates the testicles to produce more testosterone.

‘Enclomiphene is a drug that does not hold a licence for human use anywhere in the world and which was turned down repeatedly by the US regulator, the FDA,’ says Professor Quinton. This was because of a lack of data showing an improvement in symptoms.

‘The BSSM recently released a position statement on enclomiphene where it conclude that it should be “limited to experienced clinicians within specialist or research settings” – which I don’t think this [Balance My Hormones prescription] would fall into,’ adds Dr Bonnie Grant, a clinical research fellow at Imperial College London.

My final consultation was at the Harpal Clinic. During the video consultation the doctor immediately flagged my oestrogen.

‘The higher the testosterone, usually the higher the oestrogen,’ she said. She suggested I take a natural supplement DIM (diindolylmethane) to bring my oestrogen down. But she was still willing to prescribe testosterone if I wanted it – which she acknowledged would push my oestrogen higher still – but at a low dose ( £385 for a 10ml vial of testosterone cypionate, lasting around three months).

She also recommended human chorionic gonadotropin injections (£140) to preserve fertility and prevent testicular shrinkage given my age. As for the TRT, she said I could manage the increase in dose myself, at home. ‘Whenever you think you need more, you can give yourself a bit more,’ she said.

The gauge she suggested was my performance in the gym: ‘If you’re lifting weights, you can tell by how much you can lift.’

Professor Hackett’s concern is that men self-administering short-acting cypionate will be tempted to keep pushing up their dose. ‘If you put someone in charge of their own dosing, they fiddle with it. No one wants to feel below par, so men push the dose up,’ he warns. But pushed too far, this becomes dangerous.

This is clearly a problem if your testosterone results are like mine – Professor Quinton says he would not have prescribed me TRT. My findings underlined the variability between providers on what is considered ‘low’.

Channa Jayasena, a professor of reproductive endocrinology at Imperial College London has come across men with total testosterone of 16nmol/L being told by private clinics that they need treatment. ‘It is the equivalent of telling someone who is 5ft 10in that they are short,’ he says.

‘Some clinics are moving the goalposts, converting a test meant to identify a disease in men with specific symptoms into something that treats normal men.’

Voy defines low testosterone as total testosterone below 15 or up to 18 if a man’s ‘free’ testosterone is below 0.35. Professor Quinton says this ‘could capture as many as half of all men over 40’.

Balance My Hormones uses a similar free testosterone threshold. Ted’s Health sticks closely to the BSSM guidelines; Leger says ‘a testosterone level less than 12 is considered for TRT. However, in some cases, a total testosterone level up to 15 or calculated free testosterone up to 0.3 may still be considered’. Harpal says ‘we look beyond the numbers to get a full clinical picture’.

My findings aren’t a one-off.

Dr Grant co-authored a 2026 paper in The Journal of Clinical Endocrinology & Metabolism that reviewed UK testosterone clinic websites and found widespread issues ranging from offering testosterone to men with normal levels, promoting add-on drugs – and overselling benefits for energy, mood and heart health.

At the core of the problem is that many clinics recommend TRT, citing research that one in four men over 40 has low testosterone. However, this figure is ‘nonsense,’ says Professor Quinton.

Professor Jayasena adds: ‘TRT has only been proven safe in men with significantly low levels. Giving it to men with what the NHS defines as normal testosterone is experimenting.’

Up and down the country, doctors are dealing with men coming into their clinics with ‘fertility issues as a result of being given TRT – and thickened blood caused by too much TRT’, says Dr Grant. ‘Many of these men could have improved testosterone levels with lifestyle changes.’

Professor Hackett adds: ‘You can lose a couple of stone and testosterone levels will usually go back to normal pretty quickly.’

Indeed a 2025 study in the Journal of Clinical Endocrinology & Metabolism found that weight loss alone raised testosterone in men whose levels had dropped – ‘in the absence of a clinical condition, lifestyle intervention is more effective than testosterone treatment’, it concluded.

When approached for comment, Voy, Harpal Clinic, Balance My Hormones and Leger Clinic all said they operated within recognised guidelines.

Voy said my free testosterone was ‘below even the conservative BSSM threshold’ and that its protocols were ‘consistent with BSSM, American Urological Association and European Society for Sexual Medicine guidance’ – ‘our testing protocols . . . reflect published findings that diurnal variation’ (the rise and fall of testosterone through the day) is ‘substantially reduced in older men’. Voy described testosterone cypionate as ‘lawfully prescribed in the UK under MHRA rules’ and ‘pharmacologically comparable to licensed products such as Sustanon and Nebido’.

The Harpal Clinic said its approach was individualised, with ‘careful assessment, conservative prescribing, patient education, close monitoring and thoughtful adjustment’.

Balance My Hormones responded by saying enclomiphene suited ‘a specific subset of patients’ wanting to ‘maintain fertility or testicular size.

Leger Clinic said it ‘follows recognised clinical guidelines and takes patient safety seriously’, adding: ‘clinicians may differ in their interpretation of individual cases’.