Testosterone blood test: how to prepare and what happens next

Published 27 October 2026 · Matt O'Brien

Three different men waiting on a wooden bench in a bright health centre corridor in the morning: a slim young South Asian man in a grey hoodie, a heavy-set Black man in his fifties with a shaved head and grey beard in a navy work jacket, and a tall older white man with white hair and glasses in a tan cardigan with a small plaster on his inner elbow

Short answer: for a testosterone blood test, follow the instructions from whoever arranges it. The NHS says they should tell you if you need to prepare, and one result is only part of the picture. This applies to men of any age.

What time of day should a testosterone blood test be done?

Your GP, nurse or specialist decides this, so ask when you book. The NHS page on blood tests says the person arranging your test should tell you if you need to do anything to prepare.

When you book, ask what time to come in, whether you need to fast, and whether any medicine you take needs handling differently. If a slot is awkward because of shifts or school runs, say so. Asking beats guessing.

Do I need to fast?

The NHS says that for a short time before some tests, you may need to not eat or drink anything other than water. That is called fasting. For some tests you may also be asked to stop certain medicines, such as anticoagulants.

Whether that applies to your test is for the person arranging it to say. Never stop a prescribed medicine unless you have been told to.

Why one result is only part of the picture

The NHS page on the "male menopause" says a diagnosis of late-onset hypogonadism, which means a testosterone deficiency that develops later in life, can usually be made from your symptoms and the results of blood tests that measure your testosterone levels.

The NHS says you may sometimes need other tests too. Our guide to reading results covers keeping a report, its units and its reference range together, and our page on testosterone blood tests explains the different measures you may see.

Symptoms come first

If you are wondering about testosterone, something has probably changed. The NHS says that in many cases these symptoms are nothing to do with hormones. Stress, depression, anxiety, lack of sleep, too much alcohol and lack of exercise can all play a part.

It also says a later-life deficiency is uncommon, though it can happen, particularly in men who are obese or have type 2 diabetes. If your results suggest a deficiency, you may be referred to a hormone specialist. See also our guides to testosterone and energy and testosterone and weight.

If erection problems keep happening, the NHS erectile dysfunction page says to see a GP or go to a sexual health clinic.

Getting your results

The NHS says you may get blood test results after a few days, and usually within a few weeks. If you hear nothing after a few weeks, contact the surgery or specialist.

If you are 16 or over and registered with a GP, you can view your test results in the NHS App. The NHS says results can be complicated, so ask to talk to a healthcare professional if you do not understand them.

When to get help

Routine: book a GP appointment if tiredness, low mood, low sex drive or erection problems keep going.
Urgent: ask for an urgent GP appointment or get help from NHS 111 if you have aching or discomfort in a testicle that worries you, a lump, swelling, or a change in the shape or feel of a testicle.
Emergency: go to A&E or call 999 if you have sudden, severe pain in a testicle, testicle pain with feeling or being sick or tummy pain, or pain that has lasted more than an hour or continues at rest. The NHS testicle pain page says not to drive yourself to A&E.

From Matt

"You do not need to measure everything. You do need to pay attention to anything that might call for professional advice."

In my book I suggest a few neutral notes rather than a dashboard of numbers. A short record of how you have been sleeping and feeling is useful context to take alongside any result.

Your next step

Track your energy and sleep in My Timber for a couple of weeks, then take your notes to your appointment. I'm not a clinician, so talk to your GP about your own tests and results.

FAQ

What time of day should a testosterone blood test be done? Ask whoever arranges your test, as the NHS says they should tell you how to prepare.

Should I fast before a testosterone blood test? Only if you are told to. The NHS says some tests need fasting for a short time.

Is one testosterone result enough? The NHS says a diagnosis can usually be made from your symptoms and blood test results together.

Sources

Last updated 27 October 2026.