Testosterone Blood Test

• Testosterone (measured): total testosterone in serum, reported in nmol/L.

This single test does not include SHBG, LH, FSH or oestradiol. Free testosterone and the free androgen index (FAI) are calculated values that need an SHBG result alongside testosterone, so they cannot be derived from this test. Our male and female hormone profiles include SHBG and the FAI if you or your clinician need them.

Testosterone is the body's main androgen. In men it is produced mostly by the Leydig cells of the testes. The hypothalamus releases gonadotrophin-releasing hormone, which prompts the pituitary gland to release luteinising hormone (LH), and LH in turn stimulates the testes. Rising testosterone feeds back to the brain and dampens LH, which keeps levels within a working range. In women, the ovaries and adrenal glands make smaller amounts, and some is formed in body tissues from precursor hormones.

Testosterone supports sex drive, erectile function and sperm production in men, and contributes to muscle, bone and red blood cell production in both sexes. In the bloodstream most of it is attached to sex hormone binding globulin (SHBG) or albumin; only around 1 to 4% circulates unbound.

Levels follow a daily rhythm. In one study, testosterone at 4pm was 20 to 25% lower than at 8am in men aged 30 to 40, narrowing to about 10% by age 70, and the authors recommended morning sampling at all ages.

Endocrine Society and British Society for Sexual Medicine guidelines advise that low testosterone in men (hypogonadism) is diagnosed only when consistent symptoms and signs occur with consistently low results, confirmed by a repeat fasting morning test. LH and FSH then help separate testicular from pituitary causes. In women, the 2023 international polycystic ovary syndrome (PCOS) guideline uses total and free testosterone to assess raised androgens, preferably measured by liquid chromatography tandem mass spectrometry (LC-MS/MS).

Reference ranges depend on sex, age and the laboratory's method, so always read your result against the range printed on your report. As an illustration, one NHS laboratory quotes 6.9 to 23.2 nmol/L for men aged 22 to 49 and 0.3 to 1.2 nmol/L for women of the same age. Other laboratories use different figures.

There is no single universal cut-off. The Endocrine Society gives a lower limit of 9.2 nmol/L for healthy young men, valid only for assays standardised to a specific US reference programme. The European Male Ageing Study proposed a research definition of late-onset hypogonadism: at least three sexual symptoms together with total testosterone below 11 nmol/L and free testosterone below 220 pmol/L.

Common reasons for a low or borderline result that are not disease

• An afternoon or evening sample
• A recent or current illness, or short-term medicines such as opioids
• Low SHBG, which is common with obesity and lowers total testosterone even when the unbound fraction is adequate
• Heavy alcohol use, or previous anabolic steroid use, which suppresses the body's own production

Higher than expected results

In men this is usually due to testosterone or anabolic steroid use. In women it is commonly associated with PCOS and rarely with an ovarian or adrenal tumour; rapidly progressing hair growth or deepening of the voice needs prompt GP assessment. The combined pill raises SHBG and suppresses androgen production, which makes female results hard to interpret, and routine immunoassays are less accurate than mass spectrometry at the low levels found in women.

A single low result should be repeated with an early-morning sample before any conclusion is drawn. Where a result may need medical attention, we advise you to see your GP and, with your consent, we can write to your GP.

The European Male Ageing Study found that poor morning erections, low sexual desire and erectile dysfunction were the symptoms most consistently linked with low testosterone in men aged 40 to 79. Tiredness and low mood were also associated but have many other causes. For women, testosterone is one of the tests used when periods are irregular or there are signs of raised androgens, interpreted with symptoms, examination and other hormone results.

If you are already prescribed testosterone, monitoring should follow your prescriber's plan, including the timing of the sample relative to your dose. Guidelines also recommend regular checks of haematocrit and, in older men, PSA during treatment. Juvenology Clinic does not prescribe testosterone and does not offer hormone treatment.

May be useful if you

• have symptoms such as reduced sex drive or erectile difficulties and want a morning result to share with your GP
• are a woman being assessed for irregular periods, hirsutism or suspected PCOS and have been advised that a testosterone result would help
• need to repeat an earlier result with a properly timed morning sample

May not be the right choice if you

• feel well and have no symptoms: guidelines do not support routine screening
• are unwell or recovering from an illness: wait until you have recovered
• are hoping to obtain testosterone treatment: Juvenology does not prescribe, and treatment decisions belong with your GP or a specialist

• Established use: measuring morning testosterone, with repeat testing, as part of assessing symptoms of hypogonadism in men and androgen excess in women.
• Population associations: average testosterone falls gradually with age in men, and lower total testosterone is more common in men with obesity, partly because SHBG is lower. These are associations and do not show that low testosterone causes ageing-related conditions.
• Emerging research: whether treating older men who have modestly low testosterone and few symptoms improves long-term health remains under study.
• Unproven: claims that raising testosterone slows ageing are not supported by current evidence. The Endocrine Society does not recommend routine testosterone screening of the general male population.

• Time and fasting: book a morning appointment, ideally around 9am, and where possible fast overnight beforehand (water is fine), as guidelines recommend a fasting morning sample.
• Illness: postpone if you are unwell or have been recently.
• Medicines: tell us about testosterone, anabolic steroids, opioids, hormonal contraception, HRT or any other hormone medicine. Do not stop or change prescribed medicine for this test.
• Biotin: high-dose biotin supplements can interfere with some laboratory immunoassays. Mention any biotin or hair, skin and nail supplement when you book so we can advise you.
• Periods: if you have periods, note the first day of your last period on your form.

Choose how your sample is taken when you book. We confirm the collection option, any collection fee and the expected turnaround time before you book.

• Juvenology Clinic, Maidstone (82 King Street, Maidstone ME14 1BH): Available.
• Partner clinic near you, anywhere in the UK: Available on request. We confirm availability for your postcode before you book.
• Postal home finger-prick kit: Ask before ordering. We offer a home kit only where the laboratory confirms this test is suitable for a finger-prick sample.

Sample: Venous blood sample (serum); finger-prick suitability confirmed by the laboratory

Collection notes: Take the sample in the morning, ideally around 9am and after an overnight fast where possible. If a home finger-prick kit is offered, collect it in the morning and post it the same day. Postpone if you are unwell.

The price of this test covers laboratory analysis and the laboratory's results report. The report lists each result beside the laboratory's reference range.

Beyond the blood test: optional support, priced separately

• Personalised written interpretation report: £50
• General consultation: £50
• Results consultation (results discussion and follow-up advice): £100
• Personalised programme: from £150, after we assess whether a programme suits you

Consultations are with Marina, an NMC-registered nurse. She explains what your results show and how they relate to lifestyle. No prescription service is offered with these tests.

If a result suggests you need medical follow-up, we will recommend that you see your GP and, with your consent, can provide a letter to take with you. A blood test cannot rule out every condition. If you have symptoms, speak to your GP or NHS 111, and call 999 in an emergency.

Is this total or free testosterone?

It measures total testosterone. Free testosterone is usually calculated from total testosterone and SHBG, so it needs a hormone profile that includes SHBG.

Why does the sample need to be taken in the morning?

Testosterone peaks in the morning and falls through the day. An afternoon sample can look low in someone whose morning level is normal, particularly in younger men.

My result is below the range. What happens next?

Guidelines recommend repeating the test with a fasting morning sample. If it is low again, your GP may check LH, FSH and other hormones to look for a cause. Please do not start any treatment on the strength of one result.

Can Juvenology prescribe testosterone if my level is low?

No. Juvenology Clinic does not prescribe testosterone or other hormone treatment. With your consent we can write to your GP with your results.

Is interpretation of my result included?

The price covers laboratory analysis and the laboratory's report with reference ranges. If you would like help understanding it, you can add a personalised written interpretation report (£50) or a results consultation (£100).

1. Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism, 2018;103(5):1715–1744. https://www.endocrine.org/clinical-practice-guidelines/testosterone-therapy
2. Hackett G, et al. British Society for Sexual Medicine Guidelines on Adult Testosterone Deficiency, With Statements for UK Practice. Journal of Sexual Medicine, 2017;14(12):1504–1523. https://doi.org/10.1016/j.jsxm.2017.10.067
3. The effect of diurnal variation on clinical measurement of serum testosterone and other sex hormone levels in men. Journal of Clinical Endocrinology & Metabolism, 2009;94(3):907–913. https://doi.org/10.1210/jc.2008-1902
4. Wu FCW, et al. Identification of late-onset hypogonadism in middle-aged and elderly men. New England Journal of Medicine, 2010;363(2):123–135. https://doi.org/10.1056/NEJMoa0911101
5. Teede HJ, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Human Reproduction, 2023;38(9):1655–1679. https://doi.org/10.1093/humrep/dead156
6. Testosterone test. Lab Tests Online UK. https://labtestsonline.org.uk/tests/testosterone-test
7. Sex Hormone Binding Globulin (SHBG). Lab Tests Online UK. https://labtestsonline.org.uk/tests/sex-hormone-binding-globulin-shbg
8. Testosterone: test information. University Hospitals of North Midlands NHS Trust Pathology. https://www.uhnm.nhs.uk/hospitals-and-services/pathology/tests/testosterone/