Testosterone Levels by Age: UK Low Results Need a Morning Retest
For adult men, total testosterone usually sits around 8.6–29.0 nmol/L (249–836 ng/dL) between 17 and 50, with a slightly lower range after that. Levels peak in early adulthood, then drift down gradually, and the spread between men widens with age. UK clinicians treat a result under 8 nmol/L as consistent with low testosterone, but only after repeat morning tests.
TL;DR:
- Schedule two morning total testosterone tests at least one week apart, follow your laboratory’s fasting instructions, and book them at similar times.
- For results from 8 to 12 nmol/L, clinicians may calculate free testosterone and check SHBG, LH, and FSH to investigate the cause.
- Illness, obesity, opiate medicines, supplements, and altered SHBG can distort a single result, so borderline readings need context beyond total testosterone alone.
- Persistent changes in sex drive, erections, energy, mood, or muscle strength warrant discussion with a GP because each symptom can have other causes.
- Weight loss, good sleep, and resistance exercise may support testosterone, but lifestyle changes cannot treat a confirmed medical deficiency.
Table of Contents
- What are normal testosterone levels by age band?
- How does testosterone change as you get older?
- How do you test testosterone and read the result?
- Why can a single testosterone result mislead you?
- Which signs and symptoms should prompt a test?
- How do testosterone levels differ between men and women?
- Do exercise, diet, sleep and stress change your testosterone?
- What can low or high testosterone mean for your health beyond symptoms?
- Can you support healthy testosterone naturally?
- Why should you read testosterone alongside other hormone tests?
- What should you do if your result is unexpected?
- Rapidtest options for a quick first check at home
- FAQ
- Sources
What are normal testosterone levels by age band?
Here is a decade-by-decade view, so you can see roughly where a result might land. The age bands are our own grouping of the commonly cited adult ranges, which MedlinePlus gives in two blocks: 17 to 50, and over 50. Within each block, the range is the same, and individual men sit anywhere inside it.
| Age band | Typical total testosterone (nmol/L) | Typical total testosterone (ng/dL) |
|---|---|---|
| 17–50 | 8.6–29.0 | 249–836 |
| 20–29 | 8.6–29.0 | 249–836 |
| 17–50 | 8.6–29.0 | 249–836 |
| 17–50 | 8.6–29.0 | 249–836 |
| Over 50 | 6.7–25.7 | 193–740 |
| Over 50 | 6.7–25.7 | 193–740 |
| Over 50 | 6.7–25.7 | 193–740 |
Treat the table as a reference, not a diagnosis. Laboratories use different methods, so NHS trust documents note that reference ranges can differ by method and laboratory. If your lab report prints a slightly different range, that is normal, and the range on your own report is the one your clinician will use.
Two things are worth keeping in mind when you read a table like this. First, sitting near the bottom of a range does not mean something is wrong. A man whose result is near the lower end of the range and has no symptoms is in a very different position from someone with a similar result who is exhausted and has lost his sex drive. Second, a “normal” range is built from a population, so it describes what most healthy men look like, not what is ideal for you.
How does testosterone change as you get older?
Testosterone peaks in the late teens and stays high for two to three decades before it begins to fall. The decline is slow, which is why most men never notice a sudden drop. Large population studies back this up. The Massachusetts Male Ageing Study is the foundational dataset that most age-trend discussions draw on, and UK Biobank analyses show a declining trend in mean total testosterone across men aged 40 to 69.
What the numbers mean in practice:
- The average falls, but individuals vary widely. Two men of the same age can have very different results, and both can be healthy.
- Older age groups show more spread. Illness, weight and medicines pile up with age, so the gap between the lowest and highest results widens.
- Different studies report different decade figures. Cohorts differ in who they recruit, how they measure and how healthy the men were, so no single chart is the final word.
- Total and free testosterone do not move together. SHBG, the protein that binds testosterone, rises with age, which leaves less hormone free to act.
That last point matters most. Total testosterone is the figure on most reports, but free testosterone is the portion your body can actually use.
Free testosterone shows a more pronounced decline with age, with some studies estimating about 4.5 pmol/L per year. That is why a total result that looks acceptable can still hide a lower level of usable hormone in an older man.
How do you test testosterone and read the result?
Testosterone follows a daily rhythm, highest in the morning. UK guidance therefore asks for morning blood collection, around 0900h, and a single low reading is not enough on its own. The same guidance recommends two morning total testosterone measurements at least one week apart before confirming a deficiency. A clinical guideline template used by an NHS trust goes further and asks for two morning fasting measurements, because of that circadian rhythm.
The practical UK thresholds look like this:
- Under 8 nmol/L: consistent with hypogonadism.
- 8–12 nmol/L: borderline. This may represent hypogonadism, and clinicians often calculate free testosterone and weigh the result against your symptoms.
- Over 12 nmol/L: usually not hypogonadal.
If two tests are needed, you might wonder why it matters so much. One practical explanation is on a partner blog about why two morning tests matter for hormone-related fatigue, which walks through the same logic from a clinic’s side.
Clinicians often add other blood tests to find the cause of a low result. SHBG helps interpret borderline totals. LH and FSH show whether the problem starts in the testes or in the signals from the brain. Biochemical evaluation distinguishes primary from secondary causes through LH and FSH patterns, and PSA monitoring is advised for men over 45, or at higher risk, when treatment starts.
Here is a short checklist for the day of your test:
- Book the earliest morning appointment you can.
- Follow your lab’s advice on fasting. Some ask for it, some do not.
- Tell the phlebotomist about every medicine and supplement you take, especially biotin.
- Skip heavy exercise the day before, and try to sleep properly the night before.
- Keep a note of the date and time, so a repeat test can match the first.
Pro Tip: Book your repeat test at the same time of day as the first one, so the two results compare fairly.
Why can a single testosterone result mislead you?
A lot can nudge a reading up or down without telling you much about your long-term hormone health. The common modifiers are:
- Obesity and metabolic disease, which are linked with lower testosterone.
- Opiate medicines and acute illness, both of which can cause low testosterone that is not a gonadal problem.
- Biotin and other supplements, plus certain medicines and antibodies. Assays can be influenced by biotin, some medicines and heterophilic antibodies, which is why reliable assays and repeat measurements matter.
- Changes in SHBG, which can make total testosterone a poor guide to the hormone your body can use.
When the total is borderline, or SHBG is likely to be off, clinicians calculate free testosterone. That calculation often changes how the result reads, which is why a number that looked low or high on paper can look quite different once SHBG is taken into account.
Which signs and symptoms should prompt a test?
Symptoms, not a number alone, are what usually lead to testing. Low testosterone tends to show up as a cluster of changes rather than one dramatic sign. Common ones include:
- Low sex drive, and erections that are weaker or less frequent than before
- Persistent tiredness that sleep does not fix
- Low mood, irritability or trouble concentrating
- Loss of muscle and strength despite the same exercise
- More body fat, especially around the middle
- Reduced body or facial hair, and hot flushes or sweats in some men
Here is the catch: almost every item on that list also has other causes, such as poor sleep, stress, thyroid problems, depression or simply a busy life. So a symptom list alone cannot confirm anything. It is the reason to book a properly timed test and talk it through with a GP, who can look at the whole picture rather than just one blood result.
If you notice several of these together and they persist, consider booking a test and discussing them with a GP. If you only notice one now and then, it may be worth watching and improving sleep, activity and stress first.
How do testosterone levels differ between men and women?
Men and women both make testosterone, but at very different levels. Women have much lower ranges than men, which is why a “normal” result for one sex would look alarming in the other, and why the tables above apply to men only.
The age pattern differs too. In men, the fall is gradual across adult life. In women, hormone patterns shift around the menopause, and the picture is more complex. Studies of postmenopausal women suggest that testosterone and SHBG trends with age may differ from those in men, although SHBG tends to rise with age in both and affects how free testosterone is calculated.
For women, testosterone testing is usually part of a wider investigation, for example of irregular periods, excess hair growth or fertility concerns. It is rarely interpreted alone, and a woman should not compare her result with a men’s chart. If you are a woman reading this, ask your clinician for the range that matches your lab and your stage of life.
Do exercise, diet, sleep and stress change your testosterone?
Yes, though the effects are usually modest compared with illness or medicines, and they look a little different at different ages.
In younger men, regular strength training, enough sleep and a steady, adequate diet help keep levels healthy. Crash dieting, heavy drinking and chronic sleep loss can pull them down.
In middle age, weight gain around the waist becomes the big lever. Carrying extra body fat is linked with lower testosterone, and losing it can help levels recover. Work stress and poor sleep tend to build up in these years too.
In older men, staying active matters for muscle and metabolic health, and good sleep still counts. Expect lifestyle changes to support your levels rather than reverse the age-related drift.
Chronic stress deserves a mention. Ongoing pressure raises cortisol, and a body under constant strain is not set up to prioritise reproductive hormones. Short, sharp stress passes. The long, grinding kind is what tends to cause trouble.
None of this replaces proper testing. If you are worried about a result, change one thing at a time, give it a few months, and then repeat the morning test.
What can low or high testosterone mean for your health beyond symptoms?
Low testosterone is not only about libido and energy. Over time it can go hand in hand with loss of muscle and bone strength, more body fat and changes in mood and thinking. Reviews such as Harvard Health’s look at testosterone, ageing and the mind discuss links with cognition and mood. A low result can also be a signal of something else going on, such as obesity, metabolic disease or a medicine effect, so it is worth treating as a prompt to look wider.
At different ages, the concern shifts. In younger men, a low level may raise questions about fertility and development. In older men, the focus tends to be on bone, muscle, mood and general vitality.
High testosterone is less common in men and usually has an external cause, such as testosterone or anabolic steroid use. Taking extra hormone can switch off the body’s own production, which can affect fertility, and it needs medical supervision. If a result comes back unexpectedly high and you are not taking anything, that deserves a conversation with a clinician too, because a cause should be found rather than assumed.
Can you support healthy testosterone naturally?
You can support healthy levels, within limits. The most sensible steps are also the dullest:
- Sleep properly. Aim for regular, sufficient sleep, since testosterone is released largely overnight.
- Move more, and lift some weights. Resistance training suits most ages, adapted to your fitness.
- Manage your weight. Reducing excess body fat is one of the more reliable ways to help.
- Eat enough, and eat well. Avoid extreme dieting and heavy drinking.
- Keep stress in check. Walking, time outdoors and a real day off all count.
- Review your medicines. Some, such as opiates, can lower testosterone, so ask your GP before changing anything.
Age-appropriate matters. A man in his twenties can push training harder. A man in his sixties should build up gradually and may want advice on safe loading. In every case, these measures support your own production. They will not rescue a genuine medical deficiency, which needs proper assessment. Be wary of products that promise to “boost” testosterone dramatically, because the evidence behind most of them is thin.
Why should you read testosterone alongside other hormone tests?
Testosterone is one piece of a connected system. On its own, a total result tells you how much is circulating. Alongside other tests, it tells you why. SHBG shows how much of the hormone is tied up. LH and FSH show whether the testes or the brain’s signalling is the weak link, which is how clinicians separate primary from secondary causes. Thyroid function, blood sugar and, for some men, prolactin can all colour the picture, because several conditions mimic low testosterone.
This is also why one number rarely settles anything. A borderline total with a high SHBG tells a different story from the same total with a normal SHBG. A low testosterone with low LH points in a different direction from low testosterone with high LH.
If you do start with a quick at-home check, treat it as the opening step, not the full picture. Whatever it shows, a clinician can order the matching panel and interpret the pieces together.
What should you do if your result is unexpected?
Don’t panic, and don’t act on one number. Repeat the test in the morning, at least a week later, because day-to-day swings, a poor night’s sleep or an interfering supplement can all skew a single reading. In the meantime, write down your symptoms, when they started and what else has changed, such as weight, medicines, stress or sleep. Take that list to your GP.
Remember that a gradual decline with age is common, and that treatment decisions are driven by symptoms and confirmed results, not by a figure on its own. Further tests usually come first. If your result is low and you feel well, the sensible response is often to recheck and watch. If it is low and you feel unwell, ask for a proper work-up.
— Jack
Rapidtest options for a quick first check at home
Our relevant ranges are Mens Health Screening, Fertility Insight Test Kits and Health Marker Screening Test Kits. They are a starting point, not a diagnosis, so please see a clinician for persistent symptoms or an abnormal result. Browse the kits at Rapidtest when you are ready.
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
FAQ
What are normal testosterone levels per age?
For men aged 17 to 50, the commonly cited range for total testosterone is 8.6–29.0 nmol/L (249–836 ng/dL). For men over 50, it is slightly lower, at about 6.7–25.7 nmol/L (193–740 ng/dL). Your own lab’s range is the one that counts.
Is 300 testosterone low for a man?
The interpretation depends on the unit and the lab’s reference range. In the UK, results in the 8–12 nmol/L range may represent hypogonadism, so clinicians consider symptoms and may assess free testosterone. Clinicians usually repeat the test and look at symptoms and free testosterone before drawing a conclusion.
How can you tell if a man has good testosterone levels?
A result inside the lab’s reference range, confirmed on a properly timed morning test, together with an absence of symptoms, is a good sign. In the UK, a level above 12 nmol/L is usually not considered hypogonadal. Numbers and how you feel should both be considered.
What are signs of low testosterone in men?
Common signs include low sex drive, weaker erections, tiredness, low mood, reduced muscle and more body fat. These overlap with many other conditions, so a morning blood test is needed to tell them apart.