Low Testosterone Blood Test Results Explained
Short answer: low testosterone is diagnosed from symptoms plus blood tests, not a single number. UK guidance from the British Society for Sexual Medicine suggests treatment may be considered when total testosterone is below 12 nmol/L, or free testosterone below 225 pmol/L, on two separate early-morning samples, together with symptoms.
Why timing matters
Testosterone is highest in the morning and falls through the day. Tests should be taken before 11am, ideally after fasting, and a low result should always be repeated, because illness, poor sleep, heavy exercise and alcohol can lower it temporarily.
What the results mean
Total testosterone: the main screening result. Borderline levels need interpreting alongside SHBG and free testosterone.
SHBG: the protein that binds testosterone. High SHBG can leave less testosterone available to the body even when the total looks acceptable.
Free testosterone: the active portion, usually calculated from total testosterone, SHBG and albumin.
LH and FSH: show whether the problem starts in the testes or the pituitary gland, which changes the next steps.
Prolactin, full blood count and PSA: are often checked before any treatment is considered.
Common symptoms of low testosterone
Low sex drive, erectile problems, fewer morning erections, tiredness, low mood, poor concentration, loss of muscle and increased body fat. Many of these have other causes too, which is why both symptoms and repeated tests matter.
What to do next
Start with our Hormonal Health blood test, which includes testosterone, SHBG, free testosterone, LH and FSH. If your result is low or borderline, book a private clinician consultation to go through it with our Advanced Clinical Practitioner, by phone UK-wide from £50 or face to face in Crewe. Find out more about our low testosterone and TRT clinic.
Frequently asked questions
What is a normal testosterone level for a man?
Laboratory ranges vary, but most adult men fall roughly between 8 and 30 nmol/L. Levels above 12 nmol/L are generally considered adequate; levels below 8 nmol/L on repeat testing are usually low.
Can I raise testosterone without treatment?
Sometimes. Losing excess weight, better sleep, regular exercise and cutting down on alcohol can all improve levels, especially when results are borderline.
Is a home finger-prick test accurate?
Validated finger-prick tests are useful for screening when taken correctly in the morning. Borderline or low results should be confirmed with a repeat sample.
Related reading
This article is general information based on UK guidance. It is not personal medical advice. If you are worried about your symptoms or results, speak to a clinician.
