A prolactin test is done to measure the level of the hormone in your bloodstream. It is mainly responsible for milk production in lactating women and is named after the same function. Although it helps in a number of reproductive, metabolic, immunity-related, and behavioral functions in the body.

Prolactin is produced in the pituitary gland as well as the breasts, brain, uterus, skin, adipose tissue, prostate gland, immune cells.

Naturally, the levels of prolactin are higher in women who are pregnant or have just given birth but it may be high even in non-pregnant women and in men.

It is also called the Milk hormone, PRL, Luteotropic hormone, LTH, Lactotropin

Prolactin testing

What is the use of Prolactin test?

Along with some other hormone tests, this test is used to:

  • Find the reason for infertility
  • Check the functioning of pituitary gland
  • Find the cause of irregular periods in women
  • Check the reason for erectile dysfunction in men
  • Find the reason for galactorrhea—the product of milk in women without a pregnancy
  • Diagnose tumors in which excessive prolactin in produced. They are called prolactinomas

When should you do the this test?

The prolactin test is recommended if you have:

  • Infertility: Conception problems in both men and women can be due to abnormal levels of LTH.
  • Headaches or vision problems: Tumors like the prolactinoma in pregnant women may cause an imbalance of hormones, and compression of the optic nerve. Headaches and reduced vision are common symptoms; in extreme scenarios it may also cause vision loss.
  • Reduced sex drive and erectile dysfunction in men: High levels of prolactin in men affect the release of luteinizing hormone, which in turn results in lowered serum testosterone. This is what causes erectile dysfunction, lowered sex drive, and even infertility.
  • Irregular or no periods in women: High LTH levels also affect the production of hormones like progesterone and estrogen in women, which can stop the ovulation and consequently lead to irregular or missed menstruation.
  • Untimely breast milk discharge: Galactorrhea, or discharge of milk when you’re not pregnant or breast-feeding can result from too much Lactotropin.
  • Tender breasts: Although this could be due to high LTH, it might usually a result of high estrogen levels.
  • Menopausal symptoms: Signs of menopause such as vaginal dryness and hot flashes may be experienced by women having elevated levels of prolactin, as it messes up the other hormones being produced by the pituitary.
  • Hypopituitarism: If the doctor suspects hypopituitarism, they may order this test along with the growth hormone.
  • Hypothyroidism: Under-active thyroid

Prolactin testing details

When to get a Prolactin test done?

Prolactin testing can be done on any day of the month even though the levels change slightly during the course of your period cycle.

Sample requirement

A small sample of blood will be taken from your vein in your arm or it can be done with an at-home testing kit with a simple prick in a finger.

At home testing is available in select locations; please get in touch via the form on this page for more information.

Any preparation needed?

There is no specific preparation needed before the prolactin test but it must be done early in the morning, preferably after 8 hours of fasting.

How long will the results take?

The lab will release your results in 1-2 days.

How does Prolactin work?

It is primarily known for milk-production in a breast-feeding mother. The hormone is released when a baby suckles on his mother’s breast for feeding. However, this hormone performs a range of other functions in the body and is rather important in the overall well-being and immunity in women as well as men.

Prolactin, besides being responsible for stimulating the reproductive systems of both men and women, also regulates the immune system, metabolism and different bodily fluids.

Production of prolactin is controlled by two main hormones: dopamine and estrogen.

It is produced and released from the pituitary gland in response to bodily functions such as eating, mating, ovulation, breast-feeding. It is secreted in pulses and is regulated by dopamine and estrogen.

Estrogen indicates the pituitary gland to increase the production of prolactin, while dopamine restrains it. Researchers have found a direct relationship between the level of Prolactin and Estradiol.

It also plays an important role in pancreatic development.

What are normal Prolactin levels?

Men< 20 ng/mL
Women (not pregnant)< 30 ng/mL
Pregnant women80 – 400 ng/mL

Different laboratories have different systems of measurement and the normal range may be variable. Make sure to discuss your results with your doctor to interpret correctly.

(The new units of measurement are pmol/l – multiply the value with 44)

What is the ideal Prolactin level for IVF?

Prolactin levels around or less than 25 ng/ml are considered ideal. High prolactin, also known as hyperprolactinemia, may cause difficulties in achieving pregnancy.

Very high levels of Prolactin could be indicative of un under-active thyroid, PCOS, or liver or kidney problems, and it may interfere with ovulation.

What if my Prolactin is low?

It is rare for people to have prolactin levels that are below normal, but it is generally indicative of an under-functioning pituitary gland (hypopituitarism).

If a woman has lower than expected LTH after delivering a baby, she may not have adequate amount of milk production for nursing.

Major medical problems are not noted in people with low levels of lactotropin, although it has been noted that their immune response may be compromised.

Drugs like Dopamine and Levodopa can also be responsible for low prolactin in your blood stream.

What are the reasons for high Prolactin levels?

Too much prolactin in your blood stream (hyperprolactinaemia)

  • Problems of the hypothalamus gland in your brain
  • Tumors of the pituitary gland
  • Hypothyroidism
  • Kidney disease
  • Stress

An acute rise in prolactin levels after chest wall injury, thoracotomy, or surgery of the chest is seen sometimes but studies have suggested that such spike is not sustained. After around 24 hours, the levels normally go down to pre-operative levels and the sudden rise in prolactin could be attributed to stress.

Benign pituitary tumors known as prolactinomas can be responsible for very high prolactin levels in your body; they can be usually treated with drugs like dopamine.

The levels of this hormone in your blood may also be temporarily raised by:

  • Medications: Antidepressants, Estrogens, H2 blockers, Opiates, Marijuana, etc.
  • High-protein diet
  • Physical or emotional stress
  • Aggressive exercise
  • Breast exam or excessive breast stimulation
For more information on Prolactin testing and to order your Lactotropin test, get in touch via the form on this page.


Pineyro, M. M., Sosa, G., Finozzi, M. R., Stecker, N., Pisabarro, R., & Belzarena, M. C. (2017). Chronic cluster-like headache in a patient with a macroprolactinoma presenting with falsely low prolactin levels: bromocriptine versus cabergoline?. Clinical case reports5(11), 1868–1873. https://doi.org/10.1002/ccr3.1208

Badal, J., Ramasamy, R., Hakky, T., Chandrashekar, A., & Lipshultz, L. (2015). Case Report: Persistent erectile dysfunction in a man with prolactinoma. F1000Research4, 13. https://doi.org/10.12688/f1000research.5743.1

 Franchimont, P., Dourcy, C., Legros, J. J., Reuter, A., Vrindts-Gevaert, Y., Van Cauwenberge, J. R., & Gaspard, U. (1976). Prolactin levels during the menstrual cycle. Clinical endocrinology5(6), 643–650. https://doi.org/10.1111/j.1365-2265.1976.tb03867.x

A Macfarlane, MD Rosin; Galactorrhoea following surgical procedures to the chest wall: the role of prolactin, Postgraduate Medical Journal (January 1980) 56, 23-25 https://pmj.bmj.com/content/postgradmedj/56/651/23.full.pdf

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