Written by Olivia Hunt
14th Mar 2023 • 3 minute read
Dr Macarena Staudenmaier
Reviewed by
Dr Macarena Staudenmaier, M.D., MSc

Prolactin is a hormone made by the pituitary gland (found in the base of your brain). It’s known for stimulating milk production during breastfeeding and helps to regulate your menstrual cycle. Prolactin levels naturally increase if you’re pregnant or breastfeeding. Men also produce prolactin but in much smaller amounts.

What causes prolactin levels to change?

Your hormones largely influence your prolactin levels. For example, in pregnancy, your prolactin levels naturally increase to stimulate milk production for breastfeeding.

High prolactin levels can sometimes interfere with your menstrual cycle if you're not pregnant. 

Low prolactin levels are uncommon but can result from a problem with your pituitary gland.

Other factors that can affect your prolactin levels include:

You can check your prolactin levels from the comfort of home by using a fertility insights test.

What are the most common symptoms of high prolactin levels?

Common symptoms of high prolactin levels include:

  • excessive milky discharge from your nipples unrelated to breastfeeding (galactorrhea)
  • changes to your menstrual cycle — like absent or irregular periods
  • difficulty getting pregnant
  • infertility
  • reduced sex drive (libido)

How to reduce your prolactin levels

The good news is, there are some things you can to reduce your prolactin levels — like avoiding wearing tight clothing around your chest or overstimulating your nipples.

You should also try to keep your stress levels down. Psychological and physical stress can increase your prolactin levels.

To reduce your stress levels, you could try:

  • mindfulness activities — like yoga or meditation
  • staying connected — make time for your friends and family
  • exercising regularly — aim for 75 minutes of high-intensity or 150 minutes of moderate-intensity activity each week
  • prioritising your sleep — aim for at least 7 hours a night
  • doing something you enjoy — like reading, journaling, painting, or any other hobbies

What causes high prolactin levels?

Pregnancy and breastfeeding are the most common cause of high prolactin levels in women.

If you’re not pregnant or breastfeeding, you should speak to your GP to find out what’s causing abnormally high prolactin levels.

If you’re also experiencing headaches or changes in your vision, speak to your GP sooner.

The most common causes of high prolactin levels include:

  • pregnancy and breastfeeding
  • antipsychotic medications — like haloperidol and chlorpromazine
  • cyclic antidepressants — like clomipramine
  • some drugs used to treat gastrointestinal symptoms — like metoclopramide and domperidone
  • chronic stress
  • polycystic ovary syndrome (PCOS)
  • a thyroid disorder — like an underactive or overactive thyroid

If you’re pregnant or breastfeeding, there’s no need for alarm.

But you should ask your GP for advice if you have symptoms like: 

  • changes to your period
  • milky discharge from your nipples
  • reduced sex drive
  • difficulty getting pregnant

If you’re experiencing frequent headaches or changes to your vision, speak to your GP sooner.

What causes low prolactin levels?

It’s rare, but sometimes a problem with your pituitary gland might cause this. 

Some problems with your pituitary gland can also cause low levels of other hormones — like luteinising hormone (LH) and follicle-stimulating hormone (FSH). 

You might consider flagging this result to your GP. They'll consider the full range of your results and your medical history.