In short: A hormone blood test measures specific hormones in a small sample of blood to help explain symptoms such as tiredness, irregular periods, low libido, weight change or low mood. The right tests depend on your symptoms, sex, age and medicines, and timing matters: some hormones must be checked in the morning or on particular days of the menstrual cycle. Results should always be interpreted by a clinician alongside your symptoms, not on their own.

This guide, written by a Ready Health prescribing pharmacist, explains which hormones are commonly tested, how to prepare, and what results can and cannot tell you.

What is a hormone blood test?

Hormones are chemical messengers made by glands such as the thyroid, adrenal glands, pituitary gland, ovaries and testes. A hormone blood test measures the level of one or more of these messengers at the moment the sample is taken. Because many hormones rise and fall through the day or across the month, a single result is a snapshot, which is why clinicians look at results together with symptoms and sometimes repeat tests.

Which hormones are commonly tested?

Test	What it mainly reflects	When it may be considered
TSH and free T4 (sometimes free T3)	Thyroid function	Tiredness, weight change, feeling cold or hot, palpitations, hair or skin changes
Testosterone (with SHBG, LH and FSH)	Testicular function in men; also checked in women in some situations	Low sex drive, erectile problems, low energy; in women, excess hair growth or acne
Oestradiol, FSH and LH	Ovarian and pituitary function	Irregular or absent periods, fertility questions, suspected early menopause
Progesterone	Whether ovulation has occurred	Fertility investigations, timed to the second half of the cycle
Prolactin	Pituitary hormone linked to milk production	Irregular periods, nipple discharge, low libido, some headaches
Cortisol	Adrenal function	Suspected adrenal insufficiency or excess, usually as part of specialist assessment
HbA1c and glucose	Average blood sugar (insulin effect)	Tiredness, thirst, weight change, diabetes risk

A hormone test is rarely ordered in isolation. Depending on symptoms, a clinician may also suggest a full blood count, ferritin, vitamin B12, folate, vitamin D, kidney and liver function, or cholesterol, because these can cause similar symptoms.

How should I prepare for a hormone blood test?

Testosterone: usually taken in the morning (roughly 7am to 11am) when levels are highest. A low result is normally repeated on a second morning before any conclusion is drawn.
Cortisol: a morning sample (around 9am) is usual, because levels are highest soon after waking.
Female reproductive hormones: FSH, LH and oestradiol are often checked on days 2 to 5 of the cycle; progesterone is checked about 7 days before an expected period (day 21 of a 28-day cycle).
Hormonal contraception and HRT: these change many reproductive hormone results. Tell the clinician what you take; do not stop any medicine without advice.
Biotin supplements: high-dose biotin (often in hair, skin and nail products) can interfere with some laboratory tests, including thyroid tests. Ask whether you should pause it beforehand.
Fasting: not needed for most hormone tests, but may be requested if glucose or lipids are included.

Can a blood test diagnose the menopause?

Usually not. NICE guidance (NG23) says that for women over 45 with typical symptoms, perimenopause and menopause are diagnosed from symptoms, without blood tests. An FSH test may be considered in women under 45 with symptoms, and is important when premature ovarian insufficiency is suspected under 40. Hormone levels fluctuate a lot during perimenopause, so a single normal result does not rule it out.

What can hormone test results tell me, and what can they not?

Results can show whether a level sits inside or outside the laboratory's reference range and can point towards conditions such as an underactive or overactive thyroid, low testosterone, polycystic ovary syndrome (PCOS) or a prolactin problem. They cannot, on their own, explain every symptom. Reference ranges vary between laboratories, a borderline result may simply need repeating, and many symptoms such as fatigue have several possible causes. An abnormal result may lead to further tests, a GP referral or specialist input.

Hormone blood tests in Wigan and Standish: what to expect

At a private clinic appointment, a clinician will ask about your symptoms, medical history and medicines, agree which tests are appropriate, and explain any timing or preparation needed. A blood sample is taken from a vein in the arm and sent to an accredited laboratory. When the results are back, a clinician explains them and recommends next steps, which may include lifestyle advice, a repeat test or referral to your GP. Any treatment that requires a prescription is only offered if a prescriber decides it is clinically suitable after assessment.

Frequently asked questions

Do I need to fast for a hormone blood test?

Most hormone tests do not need fasting. If glucose or cholesterol is being checked at the same time, you may be asked to fast; follow the instructions you are given.

What time of day should testosterone be tested?

In the morning, ideally before 11am, because testosterone is highest early in the day. A low reading is usually confirmed with a repeat morning test.

Can I test my hormones while on the pill?

You can, but combined hormonal contraception suppresses FSH, LH and oestradiol, so these results may not reflect your natural levels. Discuss this with the clinician before testing.

Are home finger-prick hormone tests reliable?

Some finger-prick tests are processed by accredited laboratories, but sample quality can vary and certain hormones are better measured from a venous sample. Whichever method you use, results should be reviewed by a clinician.

Will my GP accept private test results?

Many GPs will consider results from an accredited laboratory, although they may repeat tests to meet local pathways. Sharing your results and the clinician's summary helps continuity of care.

Key takeaways

Hormone blood tests help investigate symptoms but are only meaningful alongside a clinical assessment.
Timing matters: testosterone and cortisol are best tested in the morning; reproductive hormones are often timed to the menstrual cycle.
Contraception, HRT and supplements such as biotin can affect results.
Most women over 45 do not need a blood test to diagnose perimenopause or menopause.
Abnormal or borderline results may need repeating or further investigation.

Sources and further reading

Last reviewed: October 2026 by Shamir Patel, Independent Prescribing Pharmacist, Ready Health. This article is general information and does not replace advice from your own clinician.

If you would like to discuss symptoms and arrange appropriate tests, you can book a blood test consultation at Ready Health in Standish, Wigan. You can also read more in our guides to hormone health checks for men and women and thyroid testing.

Hormone Blood Tests: What They Show and How to Prepare