Low testosterone is diagnosed on symptoms and repeated blood tests together, never on one number. Where it genuinely is the cause, treatment can make a substantial difference to how a man feels. How it is properly assessed, what the treatments involve, and how to tell the difference.
Testosterone deficiency, also called hypogonadism, low testosterone or low T, and informally andropause, means the body is not producing enough testosterone for what it needs. Testosterone does a great deal.
Desire, erections, orgasm and sexual function generally.
Drive, motivation, concentration, mood and general sense of wellbeing.
Lean mass and strength, and bone density, which is why long-standing deficiency raises fracture risk.
Body fat and where it sits, insulin sensitivity, and cardiovascular risk.
Red cell production, which is also why haematocrit is monitored on treatment.
Sperm production depends on the testosterone made inside the testes, which is why replacement suppresses it.
A low blood result on its own is not a diagnosis. It takes symptoms alongside consistently low levels, confirmed on at least two separate occasions, and that distinction is the one most clinics skip.
One low reading diagnoses nothing, and a great many men are treated on the strength of exactly that.
The three symptoms most specific to it:
Others are common but far less specific: fatigue, low mood, anxiety, poor concentration, loss of muscle, more body fat around the middle, hot flushes, less body hair, poor sleep. Those overlap heavily with depression, thyroid disease, sleep problems and psychological difficulty, which is exactly why an unhurried assessment beats a quick blood test and a prescription.
More things than most men are told, and the cause changes what should be done about it.
Functional deficiency is the category most often oversimplified, and it is the one where treating the cause can raise testosterone meaningfully without any medication. That is always worth trying first. Levels do fall gradually with age, which for many men causes no problem at all, and for others reaches a point where symptoms start without anyone connecting the two.
An accurate blood test is the start rather than the answer. BSSM guidance is at least two morning tests, before 11am, four to twelve weeks apart, measuring total testosterone and free testosterone calculated from SHBG. Levels move about day to day, so one reading settles nothing. Testing over a longer stretch is often sensible, particularly if you are making real lifestyle changes, and there is no rush to start testosterone when seeing what shifts on its own first is entirely reasonable.
Timing matters, though less in older men, and sleep loss, stress, heavy exercise, sex and diet all move the number. Do not over-engineer it. Have the test on a normal day for you, avoiding very hard exercise or a badly broken night in the day or two before.
The panel I use. You can do testosterone and SHBG on their own first and, if they come back low, repeat them alongside the rest:
Then the numbers get read against everything else. What they cannot tell you on their own is whether you are likely to benefit from treatment, or whether testosterone is really what is going on. That takes your history, the rest of your health, your sex life and your relationship, and it is the part an online clinic does not do.
The same number also means different things in different men. Two men with identical total testosterone can have completely different experiences, one well and one clearly symptomatic. Part of that is androgen receptor sensitivity: how responsive your cells are to the testosterone already in your blood.
The genetic factor is CAG repeat length in the androgen receptor gene. Shorter repeats mean a more sensitive receptor: those men feel testosterone strongly and may be more prone to androgenic side effects. Longer repeats mean a less sensitive one, so more testosterone is needed for the same effect, and symptoms can be clear while the blood level looks normal. It is part of why one man at 12 to 15 nmol/L feels terrible and another feels fine.
CAG analysis is not routine and does not make the diagnosis on its own. In an ambiguous case, where the picture and the numbers disagree, it adds something, and I read it alongside free testosterone, SHBG and the history.
BSSM, ISSM, EAU and the Society for Endocrinology broadly agree. With symptoms and a total testosterone below 8 nmol/L, or free testosterone below 180 pmol/L, you are likely to benefit from treatment. Between 8 and 12 nmol/L total, or 180 to 225 pmol/L free, is a grey zone where the assessment decides whether a trial is worth it. Above 12 nmol/L testosterone is less likely to be the main cause, though there is evidence of symptoms below 15.
Total is all the testosterone in your blood, most of it bound to sex hormone binding globulin and unavailable to you. Free is the fraction your body can actually use, and the evidence suggests it matters more. That is why SHBG is measured alongside: a raised SHBG, common in older men and in several conditions, makes a normal-looking total misleading.
Three explanations usually. A raised SHBG cutting your free testosterone; a less sensitive androgen receptor, related to CAG repeat length; or symptoms that were never about testosterone, and are coming from depression, thyroid disease, poor sleep or something psychological. Repeating the same blood test will not separate them. A proper assessment will.
I would not rely on one. Finger-prick testing throws up a great many errors, and it is mostly a way of drawing men into a process rather than answering the question. I would rather arrange the bloods for you at 9 Harley Street. If you genuinely cannot get to London, Medichecks will do it.
Where the diagnosis is right, treatment can work very well, and for some men it is genuinely life-changing. Energy, mood, motivation, libido, erections and body composition often improve, and men frequently describe feeling like themselves again. The care taken over the diagnosis is in service of that rather than an argument against treating: the men who do best are the ones who genuinely have the condition.
There is no single right answer. It depends on the cause, your symptoms, your priorities and your health as a whole.
Where testosterone replacement is the right route, the preparation is worth taking time over. There is no universally best one. It depends on your lifestyle, how you absorb and respond, how you feel about needles and daily routines, and what happens over the first few months. I go through all of them before we start.
The preparations, with what each is actually like:
Starting on one and switching after a few months is normal and expected rather than a setback. Getting it right takes time and attention, which is one of the arguments for staying with the same doctor throughout.
Prescribed properly and monitored properly, yes, for confirmed deficiency. That is a firmer answer than it would have been ten years ago, because two large randomised trials have since reported: TRAVERSE on cardiovascular safety and T4DM on metabolic outcomes. Neither makes testosterone risk-free, and both are precisely why the monitoring is not optional: haematocrit, PSA and hormone levels, reviewed regularly. I see you at 1, 3, 6 and 12 months in the first year and at least annually after that.
TRAVERSE, reported in 2023, randomised around 5,200 men aged 45 to 80 with symptomatic hypogonadism and either established cardiovascular disease or a high risk of it, to testosterone gel or to placebo, with a mean follow-up of just under three years. Testosterone did not increase major adverse cardiac events, meaning cardiovascular death, heart attack or stroke. That question had been open since a trial was stopped early in 2010 and an FDA safety warning followed in 2015, and a great deal of the caution built up in that period is not supported by the trial that was designed to test it.
It is not a clean bill of health, and it should not be quoted as one. The same trial found more atrial fibrillation, more acute kidney injury and more pulmonary embolism among the men taking testosterone. Its prostate substudy found no increase in high-grade prostate cancer over the period studied. And three years is three years, not a lifetime on treatment.
T4DM, reported in 2021, asked a different question. It randomised just over a thousand men aged 50 to 74 with impaired glucose tolerance or newly diagnosed type 2 diabetes, all of them enrolled in a lifestyle programme, to two years of testosterone undecanoate or placebo. Fewer men on testosterone had type 2 diabetes at two years, roughly 12% against 21%. It also raised haematocrit in a meaningful number of them, which is one of the reasons haematocrit is checked at every review rather than occasionally.
Taken together, the two trials support a narrower conclusion than either camp tends to claim. Testosterone, in deficiency that has been properly diagnosed, has better safety evidence behind it than the caution of the last decade assumed. Neither trial makes it a treatment to hand out on the strength of a borderline number and a waist measurement. And both were run with monitoring throughout, which is the part that makes their findings mean anything for an individual man rather than for a trial population.
It is an amber-list drug, which means it is usually started by a specialist, and many GPs are reluctant to prescribe it directly. Endocrinology waits are long, which is why a lot of men look privately. What you are buying is faster access and a thorough assessment, not a different drug.
One of the commonest things I see. It may be that the preparation or the dose needs changing. It may also be that testosterone was never the main cause, because fatigue, low mood and sexual difficulty are usually multifactorial. Men on TRT who are not improving are a large part of my practice, and I can assess the hormonal and the psychosexual side of it together.
Most testosterone clinics, online or not, are built around subscription prescribing, so the financial incentive is to diagnose deficiency and to keep you on a monthly prescription. That works well for revenue. It does not always work well for men. Not everyone with fatigue, low libido and low mood has testosterone deficiency as the main cause. Sometimes it is untreated sleep apnoea, or coeliac disease, or anaemia from a bowel cancer.
I have worked inside the bigger online testosterone clinics earlier in my career, and I have been approached more than once about senior clinical roles at large providers. I said no. When you are running a subscription model there is pressure, however subtle, to fit a man into the box that produces a prescription.
When you are running a subscription model there is pressure, however subtle, to fit a man into the box that produces a prescription.
What brought me back to independent practice was the men I could not help properly inside it: men who had been on TRT for years without their symptoms ever resolving, whose testosterone had been optimised over and over while the real problem was psychological, relational, or something else entirely.
So I do not run a subscription. I run a clinical practice, and I do not prescribe testosterone where I do not think it will help. If an online clinic has told you your testosterone is low and you need TRT, or you have been on it a while without feeling better, get an independent second opinion. That is exactly the conversation I am here to have.
Most testosterone clinics work on hormones alone. I am a GP and a physician who then specialised in sexual medicine and trained as a therapist, so the medical, the psychological and the relational get assessed in one place rather than across three referrals. In practice that means psychosexual therapy is available here where it is relevant, rather than being the part a hormone clinic has to send you elsewhere for.
The first consultation is an hour, and hormones are one part of it. What is actually happening and when it started, what was going on in your life at the time, your full medical history and every medication you take, and an examination where that is useful. Then the things a hormone questionnaire does not ask about: sleep, mood and mental health, alcohol, recreational drugs and any anabolic steroid use, weight, diet and exercise, work and stress, your relationship, and your sexual history.
That breadth is the point rather than thoroughness for its own sake. Fatigue, low mood and low libido are the symptoms of a great many things, and the ones that get missed when a low testosterone reading arrives early and closes the question are not obscure: sleep apnoea, depression, thyroid disease, anaemia, alcohol, a relationship in difficulty. Testosterone is one answer among several, and it should be diagnosed properly rather than assumed.
And what that looks like as a patient:
Central Health London, 23 Devonshire Place, Marylebone, London W1G 6JB, a few minutes from Harley Street. I also do video consultations for patients elsewhere in the UK and internationally.
Yes, and I see men of all orientations. As a gay man myself I understand the concerns that often bring gay and bisexual men to look for someone specific, and you can speak frankly here without having to explain the background first.
The clinic is at Central Health London, 23 Devonshire Place, Marylebone, a quiet and discreet address a short walk from Regent’s Park. Most men arrive anxious and leave relieved. You will be welcomed by reception, offered tea or coffee, and given time to settle before we start.
A first consultation is usually an hour. We go through your symptoms, your medical and family history, and your sexual experience, relationships and lifestyle: the medical, psychological and relational picture together rather than one at a time.
I will ask you a lot of questions. You do not have to answer any of them: saying "I would rather not answer that" is a complete answer and nothing follows from it. A physical examination is sometimes useful, particularly for erection problems, and it is always optional. You stay in control of the appointment throughout.
If you have had recent blood tests, send them ahead. If not I will arrange them, and I will tell you which ones need taking before 11am.
If you are in your fifties or sixties, have no GP you know well, do not much like going to the doctor, but recognise it is time to take your health seriously, this is a reasonable place to start. I often find things that matter and have been missed.
If you want help but are wary of seeing someone who is not comfortable talking about gay or queer sex, you can come to someone who does not need it explained, and who will not judge or shame you.
Men who have tried quick fixes, or had a purely medical or purely therapeutic approach that did not help. I see a lot of men for second opinions. And men of any age and in any kind of relationship who want to understand what is going on rather than be handed a prescription.
I am a GP, a sexual medicine specialist and a COSRT-registered psychosexual therapist, working at 23 Devonshire Place, Marylebone, central London, alongside NHS general practice in Hackney.
Most men reading a page like this arrived from a search rather than my homepage, so this is probably the first you have heard of me. The short version: I hold the medical, the psychological and the relational picture together in one appointment, rather than sending you to three people who each see a third of it.
More about how I workThese rarely arrive on their own. If one of these sounds closer to what you’re dealing with, start there instead.
If something doesn’t feel right, it’s worth understanding why, before deciding what, if anything, to treat.
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