What is a Prolactin Blood Test?
A prolactin blood test is a simple way to measure the level of prolactin in your blood.
Prolactin is a hormone produced by the pituitary gland, and while it’s best known for its role in helping women produce breast milk after childbirth, it plays important roles in both male and female bodies.
Below, we explain what a prolactin blood test is, what the results can tell you and why this test might be an important part of understanding your overall health.
Prolactin levels and what they tell you
A prolactin blood test measures the amount of prolactin hormone circulating in your bloodstream. Prolactin levels are normally low in men and in women who aren’t pregnant or breastfeeding. However, high or low levels can sometimes signal an underlying health issue that may need further investigation.
This test is often used to help identify hormonal imbalances, investigate the causes of symptoms such as irregular periods, infertility, or unexpected breast milk production (galactorrhoea), and monitor the function of the pituitary gland.
What is prolactin?
Prolactin is a hormone secreted by the pituitary gland, a small gland located at the base of your brain. Its primary function is to stimulate breast milk production after childbirth. However, prolactin also plays a role in metabolism, immune system regulation and reproductive health in both sexes.
Although its exact function outside of lactation isn’t fully understood, changes in prolactin levels can have noticeable effects on the body.
Why might I need a prolactin blood test?
A prolactin blood test may be recommended if you’re experiencing symptoms that could suggest a hormonal imbalance.
In women, these symptoms may include:
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Irregular or missed periods
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Infertility
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Unexplained milk production when not pregnant or breastfeeding
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Symptoms of menopause at an early age
In men, a prolactin test may be advised if you have:
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Decreased libido or erectile dysfunction
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Fertility problems
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Unexplained breast enlargement
It may also be helpful in cases of:
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Headaches or visual disturbances (which could suggest issues with the pituitary gland)
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Suspected pituitary tumours (prolactinomas)
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Unexplained fatigue, mood changes or other hormonal symptoms
What can cause high prolactin levels?
There are many potential reasons why prolactin levels may be higher than expected. Some of the most common include:
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Pregnancy or breastfeeding – Naturally raises prolactin levels
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Pituitary tumours (prolactinomas) – Usually benign but may affect hormone production
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Hypothyroidism – An underactive thyroid can cause elevated prolactin
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Certain medications – Such as antidepressants, antipsychotics or blood pressure medications
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Stress or intense exercise – These can cause temporary increases in prolactin
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Chest wall injuries or stimulation – Can trigger prolactin release
It’s important to note that a single raised prolactin reading doesn’t automatically mean something is wrong. Your results should always be interpreted alongside your medical history and symptoms.
What can cause low prolactin levels?
While high prolactin levels are more commonly tested and investigated, low prolactin levels may also indicate pituitary dysfunction, particularly if you’re experiencing symptoms such as fatigue, low libido or menstrual irregularities.
However, low levels are rarely a cause for concern on their own and often don’t require treatment unless linked to a broader hormonal issue.
What does a prolactin blood test involve?
A prolactin test is a straightforward blood test. A small sample of blood is taken, usually from a vein in your arm. It’s a quick procedure that only takes a few minutes.
To get the most accurate result:
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You may be asked to avoid eating for several hours before the test (fasting).
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Try to schedule your appointment early in the morning, when prolactin levels are more stable.
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Avoid strenuous activity, stress, or breast stimulation for 24 hours before your test.
If you are taking any medications, be sure to inform your healthcare provider, as some drugs can affect prolactin levels.
What happens if my prolactin levels are abnormal?
If your prolactin levels are elevated, your healthcare provider may recommend further tests to identify the cause. This could include:
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Thyroid function tests
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MRI scan of the brain to check for pituitary abnormalities
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Review of current medications to see if they may be influencing hormone levels
Treatment will depend on the underlying cause. For example, if a benign pituitary tumor is identified, medication may be prescribed to reduce prolactin levels and shrink the tumor. If a medication is the likely cause, your doctor may explore alternative options.
If your prolactin levels are low, additional hormone tests may be recommended to assess overall pituitary function.
Can lifestyle changes help manage prolactin levels?
In some cases, especially where stress, poor sleep or lifestyle habits are contributing to raised prolactin levels, simple changes can make a meaningful difference. By making small but consistent adjustments to your daily routine, you may be able to support more balanced hormone levels naturally.
These changes may include:
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Prioritising rest and managing stress – Chronic stress can raise prolactin levels, so incorporating relaxation techniques like mindfulness, meditation or gentle exercise may help.
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Eating a balanced diet and maintaining a healthy weight – A nutritious diet that supports overall hormonal health can be beneficial, especially when combined with stable blood sugar levels.
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Avoiding excessive exercise or overtraining – While regular activity is important, overexertion can disrupt hormone production, including prolactin.
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Reviewing medications with your healthcare professional – Certain prescribed drugs may influence prolactin levels, so it’s worth discussing any concerns with your doctor.
Take a proactive approach to your health
If you’re experiencing symptoms linked to hormone imbalance or pituitary function, a prolactin blood test can provide useful insight. Speak with your GP or healthcare provider about whether this test may be right for you.
For general health screening and support, Bluecrest Wellness offers a wide range of health assessments, available at locations across the UK to help you stay on top of your wellbeing.
