Prolactin test: normal range, what high prolactin means and price

A prolactin test measures prolactin, a hormone made by the pituitary gland, in a blood sample. Prolactin's main job is milk production, but too much of it can upset periods, fertility and sex drive in both women and men. A high prolactin has many ordinary causes, so the test is a starting point rather than an answer.

What prolactin does

Prolactin is released by the pituitary gland at the base of the brain. Its main role is to make breast tissue grow in pregnancy and to produce milk after birth, so levels are normally high in pregnancy and while breastfeeding, and low otherwise. When prolactin runs high outside pregnancy, it can interfere with how the ovaries or testes work. In women that can mean irregular or absent periods and difficulty conceiving. In men it can mean a lower sex drive and erectile problems. In either sex it can cause milk to leak from the breast.

Normal prolactin range

Prolactin is reported in ng/mL (the same number as µg/L) or in mIU/L. Using the World Health Organization standard 84/500, 1 µg/L equals 21.2 mIU/L, and the mIU/L figures below are converted that way. MedlinePlus, the US National Library of Medicine's health information service, gives these upper limits:

The Endocrine Society notes that assay-specific normal values are higher in women than in men and generally below 25 µg/L. Ranges vary between laboratories and methods, so read your result against the range printed on your report.

What a high prolactin usually points to

A high prolactin has a long list of possible causes, and several of them are temporary.

• The body's own state. Pregnancy and breastfeeding raise prolactin, and stress, exercise, sleep and sex can all push it up. A high-protein meal, a recent breast examination or nipple stimulation can raise it for a while.
• Medicines. Antipsychotics, some antidepressants, metoclopramide, opioids, verapamil, H2 blockers and oestrogens can all raise prolactin. The Endocrine Society notes that medicine-related rises usually sit between 25 and 100 µg/L.
• Other conditions. An underactive thyroid, kidney disease and cirrhosis can raise prolactin. About a third of people with kidney disease develop a high prolactin, partly because less of it is cleared. MedlinePlus also lists polycystic ovary syndrome.
• Macroprolactin. Part of the prolactin in blood can circulate as a large, less active form called macroprolactin. The Endocrine Society calls it a common cause of a raised result and suggests checking for it in people without symptoms. Laboratories can test for it with an inexpensive extra step called polyethylene glycol precipitation.
• A prolactinoma. MedlinePlus describes this benign pituitary growth as the most common cause of high prolactin. The Endocrine Society notes that larger prolactinomas typically come with values above 250 µg/L, and when a prolactinoma is suspected, doctors usually arrange an MRI scan of the pituitary.

A doctor who sees a raised prolactin usually reviews medicines, considers pregnancy, checks thyroid and kidney function, and may repeat the test to see whether it stays high, sometimes asking the lab to look for macroprolactin. The Endocrine Society recommends ruling out medicines, kidney failure, an underactive thyroid and pituitary or nearby tumours as causes.

What a low prolactin usually points to

A low prolactin is uncommon. MedlinePlus notes that it can be a sign of a pituitary disorder, and that in women who are breastfeeding it can go with making too little milk.

What moves prolactin

• Time of day and sleep. Prolactin changes through the day and rises with sleep, which is why samples are usually taken a few hours after waking.
• Stress, including the draw itself. The Endocrine Society asks for samples taken without excessive stress from the needle.
• Exercise, sex, breast stimulation and protein. Each can cause a small, temporary rise.
• Medicines. See the list above.
• Biotin. Prolactin was among the hormones in a small study where a biotin dose found in over-the-counter supplements made some assays read falsely high or falsely low.

Preparing for the test

MedlinePlus says the sample is usually scheduled three to four hours after waking, and that you may be asked to fast for several hours. The Endocrine Society says the test can be drawn at any time of day, as long as the draw is not stressful. It helps to sit quietly before the sample, to skip hard exercise and breast stimulation beforehand, and to tell the person taking the sample about every medicine and supplement you take. Do not stop a prescribed medicine for the test unless your doctor tells you to.

How Clare's panel handles prolactin

In Clare's panel, prolactin is measured by the lab. It is grouped with the female hormones but matters in men too, and the panel also includes TSH and creatinine, two of the results a doctor reads beside a raised prolactin.

Price

When we read public prices on 11 October 2026, a prolactin test on its own cost from 70 to 90 at 2 UAE providers. Prolactin is also sold within female hormone packages, and those that listed it cost from 299 to 1,800 at 8 providers. VAT was rarely stated, some package prices were offers or "from" prices, and home collection can add a fee, particularly on small orders that do not include a package.

Related tests

Prolactin is read with Thyroid-Stimulating Hormone (TSH), Luteinizing Hormone (LH) and, in men, Total Testosterone. It is part of the Female hormone test, and the Thyroid test covers TSH. Our note on how we read a thyroid panel explains the thyroid side.

Why prolactin means more over time

Because so many everyday things push prolactin up for a while, a doctor may repeat a raised result to see whether it stays high before going further. Read against your own earlier results, under the same conditions, a prolactin value says much more than it does alone. Clare is opening with a waitlist at clare.health.