Hormones and performance
Testosterone Levels by Age: What's Normal in the UK
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed April 202614 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
Quick answer
For UK men aged 18 to 49, total testosterone usually falls between 8.7 and 29 nmol/L. From age 50 it narrows to 6.7 to 25.7, averaging around 17 at peak. BSSM guidance treats below 8 as likely deficiency, and 8 to 12 as a grey zone that needs repeat morning testing.
Your result says 14 nmol/L. Your GP says “normal.” But you feel sluggish, your training has stalled, and recovery is worse than five years ago. So is 14 really normal? Or is the reference range built from unwell 80‑year‑olds?
This guide shows what testosterone looks like at each age, and when “normal” is not the same as optimal. It draws on 2023 BSSM guidelines, NHS ranges, and peer-reviewed research.
By the Helvy Medical Team · Reviewed by a qualified clinician · 14 min read
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Testosterone range checker
Enter a total testosterone result to see where it sits against the BSSM reference thresholds used in this guide. This is information, not a diagnosis.
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Build my test1. What does testosterone actually do?
Testosterone is the main androgen in men and women. Men make it mostly in the testes, driven by LH from the pituitary. Women make smaller amounts in the ovaries and adrenals.
It does far more than muscle and sex drive. It shapes bone density, red blood cells, fat storage, mood, and focus. Low levels track higher heart disease and diabetes risk.
The real problem is the reference range. Most UK labs use a very wide one, from 6 to 27 nmol/L in some NHS labs. It is broad enough that a young athlete and a 75‑year‑old with metabolic syndrome are both “normal.” Step one is knowing what your number means for your age.
2. Normal testosterone levels by age (nmol/L)
The table shows total testosterone ranges for men, from the British Society for Sexual Medicine (BSSM) and UK lab standards. All values are in nmol/L, the unit UK labs use.
| AGE | TYPICAL RANGE | NOTES |
|---|---|---|
| 18–29 | 8.7–29.0 nmol/L | Peak production. Average ~17.5 nmol/L |
| 30–39 | 8.7–29.0 nmol/L | Gradual decline begins in some men. Average ~17.3 nmol/L |
| 40–49 | 8.7–29.0 nmol/L | Range unchanged, but SHBG rises — free T may be lower. Average ~16.8 nmol/L |
| 50–59 | 6.7–25.7 nmol/L | Reference range narrows. Average ~16.5 nmol/L |
| 60–69 | 6.7–25.7 nmol/L | More men enter the grey zone. Average ~16.4 nmol/L |
| 70+ | 6.7–25.7 nmol/L | Higher comorbidity confounds readings. Average ~14–15 nmol/L |
Average total testosterone by age (nmol/L)
17.5
18–29
17.3
30–39
16.8
40–49
16.5
50–59
16.4
60–69
14.5
70+
In healthy men the average barely moves with age. The decline tracks obesity and illness, not birthdays.
Illustrative only. Below 8 nmol/L is treated as likely deficiency, 8–12 as a grey zone. Discuss your own results with a qualified clinician.
UNIT CONVERSION
UK labs use nmol/L. US labs use ng/dL. Multiply nmol/L by 28.842, so 15 nmol/L is about 433 ng/dL.
NHS ranges vary by trust too. A man at 7 nmol/L can be flagged low at one hospital and normal at the next, which is why context beats the raw number. A reading above the range matters as well: see high testosterone in men.
3. Does testosterone really decline 1% per year?
You will read everywhere that testosterone drops 1–2% a year after 30. Repeated so often, it sounds like a law. The evidence says otherwise.
A 2014 study in the European Journal of Endocrinology found no real fall in total testosterone after age 40 in men who stayed healthy and lean. The population decline tracks obesity, diabetes, and medication, not age.
This reframes the question. If your testosterone is 11 nmol/L at 45, the cause is not simply “ageing.” It may be body composition, sleep, or metabolic health, all of which you can change. When it causes symptoms, people call it the male menopause, and a blood test tells it apart from ageing.
The BSSM 2023 guidelines agree: “The decline in testosterone with ageing is predominantly explained by comorbidities, particularly obesity.”
“Although testosterone levels fall as men age, the decline is steady at about 1% a year from around the age of 30 to 40, and this is unlikely to cause any problems in itself.”
— NHS, Male menopause (andropause)
4. Free testosterone vs total: which matters more?
Total testosterone measures everything in your blood. But only 2–3% is “free,” unbound and active. The rest binds to SHBG (sex hormone-binding globulin) (about 60–70%) or albumin (about 30–40%).
Here is why that matters. A man with total T of 15 nmol/L and SHBG of 20 has plenty of free testosterone. Same total T with SHBG of 60, and most is locked up. He can have deficiency symptoms on a “normal” result. The BSSM measures free testosterone in the grey zone (8–12 nmol/L); below 0.225 is low. Our free testosterone guide covers how it is worked out and what the thresholds mean.
Ageing, an overactive thyroid, and liver disease raise SHBG. Obesity and diabetes lower it. So testing SHBG with testosterone beats total T alone. If high SHBG is the problem, our guide to increasing free testosterone covers what moves it.
5. The grey zone: 8–12 nmol/L explained
The BSSM practical guidelines define three clinical thresholds for total testosterone:
ABOVE 12 NMOL/L
Testosterone is unlikely to be the cause. Look elsewhere: thyroid, iron, vitamin D, cortisol, or sleep.
8–12 NMOL/L — THE GREY ZONE
A trial of testosterone replacement therapy (TRT) may fit if you have symptoms andfree testosterone is also low (below 0.225 nmol/L). One reading here is not enough to diagnose. Repeat it on a morning, fasted sample.
BELOW 8 NMOL/L
Deficiency is likely and treatment is usually offered. If below 5.2 nmol/L with low LH/FSH or raised prolactin, a pituitary MRI is advised to rule out a tumour.
The grey zone is where most men who feel low T land, and where most GPs call it normal. If your result landed here, our guide to borderline testosterone results shows how to confirm it.
6. At what testosterone level do symptoms appear?
Symptoms do not switch on at one number. They build as levels fall. This maps clinical data cited in the BSSM 2023 review:
| TOTAL T | COMMON SYMPTOMS |
|---|---|
| <15 nmol/L | Reduced energy, slower recovery from exercise, declining motivation |
| <12 nmol/L | Increased body fat (especially visceral), reduced muscle mass, irritability |
| <10 nmol/L | Low mood, poor concentration, sleep disturbance, loss of morning erections |
| <8 nmol/L | Erectile dysfunction, significant fatigue, hot flushes, reduced bone density |
These thresholds are rough, and people vary. A drop from 25 to 14 is a big relativechange even when 14 reads “normal.” Under 40 and genuinely low? The cause is rarely age: see low testosterone in young men and what causes low testosterone.
7. What tanks your testosterone (and it's not just age)
If the drop is mostly lifestyle and health, what drives it? The biggest factors you can change, plus the drug-related ones:
- Body fat. Fat holds aromatase, which turns testosterone into oestradiol. Losing visceral fat is the best natural move.
- Poor sleep. A 2011 JAMA study cut sleep to 5 hours for a week and testosterone fell 10–15% in young men. See sleep and testosterone.
- Medications. Opioids, SSRIs and SNRIs, steroids, finasteride, and long-term PPIs all lower it.
- Stress and cortisol. High cortisol suppresses the HPG axis. Overtraining without recovery runs you low.
- Metabolic health. Insulin resistance and diabetes link to low testosterone. Check HbA1c and fasting glucose too.
8. When and how to test (timing matters)
Testosterone runs on a daily clock. It peaks between 7 and 10am and can be 30% lower by late afternoon, so a 4pm draw reads well below the true value.
The BSSM is clear: measure it on a fasting morning sample before 10am, and repeat a low result at least 4 weeks later. See our guide to the best time to test testosterone.
What a good test should include:
- Total testosterone. The headline number.
- SHBG, to work out free testosterone.
- Free testosterone. The active fraction.
- LH and FSH, to separate testicular from pituitary causes.
- Prolactin, since a high level points to the pituitary.
- Thyroid (TSH), as thyroid problems mimic low T.
Our Complete Male Hormones panel covers testosterone, SHBG, free testosterone, and DHEA-S alongside LH, FSH and prolactin, so you can read your result.
9. What happens if your levels are low? The UK pathway
Take suspected low testosterone to your GP and the typical NHS pathway runs like this:
- First test. Total testosterone at the GP. Often not fasted or morning, so it can read falsely low.
- Repeat test.If low, a fasting morning sample follows 4–6 weeks later, with LH, FSH, and prolactin.
- Referral.If confirmed, you see an endocrinologist. Waits run 3–6 months.
- Treatment. TRT (gel, injections, or patches) is lifelong and affects fertility.
Step 1 to treatment can take 6–12 months. Many men test privately first, not to self-prescribe, but to reach the GP with full, correctly-timed results. For when the NHS will and will not test, see our guide to getting a testosterone test on the NHS.
10. Testosterone in women: the overlooked hormone
Testosterone is not only a male hormone. Women make less, but it still matters for energy, libido, bone density, and mood. It is often overlooked.
| CONTEXT | RANGE |
|---|---|
| Premenopausal | 0.5–2.4 nmol/L |
| Postmenopausal | 0.3–1.7 nmol/L (often lower) |
| PCOS (elevated) | >2.7 nmol/L may indicate hyperandrogenism |
| On testosterone therapy | Target <1.5 nmol/L (reduce dose if exceeded) |
NICE guidance (NG23) says testosterone can be considered for menopausal women with low desire when HRT has not helped, though no product is licensed for women here so it is off-label. At the other end, raised testosterone is a diagnostic criterion for PCOS, which affects about 1 in 10 UK women.
11. How to raise testosterone naturally (what actually works)
Before TRT, these moves have real evidence, by effect size. Our full guide on how to raise testosterone naturally covers each in depth, including the role of zinc. For diet, see our guide to foods that increase testosterone.
- Resistance training. Compound lifts build lean mass and cut fat. The gain is the body change, not the spike.
- Body fat reduction.Losing 10% of weight can lift testosterone by 2–3 nmol/L in overweight men.
- Sleep.7–9 hours. Production peaks in deep sleep, so treat apnoea.
- Targeted supplements. Only for a proven shortfall: vitamin D, zinc, or magnesium. “Boosters” with nothing to fix are wasted money.
- Less alcohol.Regular drinking lowers production and raises SHBG. Even 3–4 units a day counts.
Frequently asked questions
What is a good testosterone level for a 30-year-old man?
The range for men aged 18–49 is 8.7–29.0 nmol/L, averaging 17–18. Above 15 is generally healthy, but your own baseline matters more than the average. A drop from 22 to 12 is worth a look even if 12 is still “in range.”
Can you test testosterone at home?
Yes. A home finger-prick test is accurate when a UKAS-accredited lab runs it. Timing is what matters: take the sample in the morning, before 10am and fasted.
Is 15 nmol/L low testosterone?
No. 15 nmol/L is normal and above the BSSM threshold of 12. But with symptoms, check SHBG and free testosterone. A total T of 15 with very high SHBG can still leave too little active.
How much does a testosterone blood test cost in the UK?
An NHS GP test is free but often only measures total testosterone. Private home tests run £30–£50 for testosterone alone, or £100–£150 for a full hormone panel. Our Complete Male Hormones panel (£119) covers testosterone plus 8 related markers.
Does testosterone replacement therapy have side effects?
Yes. TRT shuts down natural production, shrinks the testes, and cuts fertility, working like a male contraceptive. Other effects include polycythaemia (raised red cell count, tracked with a full blood count), acne, and mood changes. It is lifelong, so thorough testing before you start matters.
Should I test testosterone if I feel fine?
A baseline in your 20s or 30s is worth it. The decline is slow, so a baseline lets any later test show your own trend, not just a population range.
Check your testosterone levels
Our Complete Male Hormones panel (£119) covers testosterone, SHBG, free testosterone, LH, FSH, prolactin and DHEA-S. Home finger-prick kit, results usually within 5 working days, UKAS-accredited UK labs.
Medical disclaimer:This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Reference ranges cited in this guide are based on BSSM guidelines and published research. They may differ from the ranges used by your local NHS laboratory. Do not make changes to medication, supplementation, or treatment plans based solely on information in this article — consult your GP or a qualified healthcare professional. All Helvy blood tests are processed by UKAS-accredited laboratories to ISO 15189.
Last updated: April 2026 · By Helvy · Medically analysed at UKAS-accredited UK laboratories
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