What is being tested?

Testosterone is the main male sex hormone. It’s produced by both males and females, although usually in much greater amounts in males.

Testosterone helps the male sex organs to mature and produce sperm. It helps with the growth of facial and body hair and deepening of the voice. It also affects your sex drive. Testosterone plays a part in the development of your muscles.

During puberty, males start to make large amounts of testosterone. It is made mainly in your testes, but also in your adrenal glands.

Women make a small amount of testosterone in their ovaries, adrenal glands and other body tissues. Some of this breaks down to form a type of oestrogen called oestradiol.

A blood test for testosterone can show how much of this important sex hormone is in your body.

Why do I need this test?

Your doctor might suggest a blood test for testosterone if:

• you are having problems getting pregnant – both males and females can be tested
• you are a male with problems getting an erection
• you are a male with a low sex drive
• you are a female but have male features, such as a lot of body hair or a low voice
• puberty has come very early, or is very late

Some diseases can also affect the amount of testosterone in your blood. These include diabetes, mumps and tumours on the testicles or ovaries.

People who drink too much alcohol can also have low testosterone levels.

How should I prepare for the test?

What you need to do before your test will depend on the blood test you’re having.

You may need to have a fasting blood test early in the morning. Check when you are last allowed to eat. Sips of water in the morning will be fine.

You can usually continue to take your usual medicines.

It’s best to check with your doctor or the pathology collection centre. Ask them if there is anything you need to do before having your blood test.

What does the result mean?

Many things can affect your testosterone blood test results, including your age, your health and what’s happening with your body. A result outside the normal range might not mean you have a health problem.

You will need to discuss the results with your doctor, what they mean, and what comes next.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

Resources and support

To learn more about blood tests you can read healthdirect's Guide to blood testing.

Pathology Tests Explained also has lots of information on blood tests including testosterone tests.

For more information about men’s health visit the Healthy Male website.