Blood test
Testosterone Test
A testosterone test measures the level of the hormone testosterone in the blood. It helps investigate low libido, fertility problems and other hormone-related symptoms.
Quick answer
Testosterone Test: what it is and what the results mean
Testosterone is the main male sex hormone, also present in smaller amounts in women. A testosterone blood test measures its level and is sometimes done with other hormones to assess the whole picture.
- Why it is done: In men it is used to investigate low libido, erectile difficulties, tiredness, reduced muscle or fertility problems; in women it may be checked for symptoms such as excess hair growth or irregular periods.
- Understanding results: A consistently low level in men, alongside symptoms, may indicate low testosterone (hypogonadism) and prompt further tests to find the cause.
What it is
Testosterone is the main male sex hormone, also present in smaller amounts in women. A testosterone blood test measures its level and is sometimes done with other hormones to assess the whole picture.
Why it is done
In men it is used to investigate low libido, erectile difficulties, tiredness, reduced muscle or fertility problems; in women it may be checked for symptoms such as excess hair growth or irregular periods.
What to expect
Because levels are highest in the morning and vary through the day, the sample is usually taken in the morning, sometimes on more than one occasion. It is a standard blood test from the arm.
Understanding the results
A consistently low level in men, alongside symptoms, may indicate low testosterone (hypogonadism) and prompt further tests to find the cause. In women, a raised level may be investigated for conditions such as polycystic ovary syndrome.
Good to know
Risks and limitations
The blood test is very safe. A single reading can be misleading because levels fluctuate, so an abnormal result is usually repeated and interpreted with other hormone tests and your symptoms.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Testosterone Test: frequently asked questions
Why is testosterone measured in the morning?
Testosterone is typically highest in the morning, so morning sampling gives the most meaningful reading. Because levels vary, a low result is often repeated before any conclusion is drawn.
What are symptoms of low testosterone?
These can include reduced sex drive, erectile difficulties, tiredness, low mood and reduced muscle mass. They have many causes, so a low blood level is interpreted alongside symptoms and further tests.
Related tests
Other blood test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Association for Laboratory Medicine / relevant professional body
Building patient-education content for tests or procedures?
We create clear, accurate, referenced medical explainers and decision aids for teams.