Prolactin blood test
In short
A typical adult prolactin result is 4.8 to 23.3 ng/mL for women and 4 to 15.2 ng/mL for men. A mildly high prolactin is common and often comes from stress, exercise, a meal or some medicines. Much higher levels make a small, usually noncancerous pituitary growth (prolactinoma) more likely. Always read your result against the range printed on your own report.
A brain hormone best known for making breast milk.
Prolactin comes from the pituitary, a small gland at the base of the brain. It drives breast milk after childbirth, and in anyone, too much of it can upset periods, fertility and sex drive. It is often checked when periods stop, when breasts leak milk outside of nursing, or when testosterone is low.
Is my Prolactin high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Female | 4.8–23.3 | ng/mL |
| Male | 4–15.2 | ng/mL |
| Female | 102–496 | mIU/L |
| Male | 86–324 | mIU/L |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your Prolactin is high
A mildly high prolactin is common and often comes from stress, exercise, a meal or some medicines. Much higher levels make a small, usually noncancerous pituitary growth (prolactinoma) more likely.
Common reasons
- Stress, exercise, sex or breast stimulation before the test
- Pregnancy or breastfeeding
- Some medicines, including some for mental health, nausea or blood pressure
- Macroprolactin, a large, mostly inactive form that some tests pick up
- An underactive thyroid
- Kidney disease, which slows how prolactin is cleared
- Less often: a prolactinoma, a small, usually noncancerous pituitary growth
If your Prolactin is low
A low prolactin is uncommon and rarely a concern on its own. It matters mainly if other pituitary hormones are low too.
Common reasons
- Normal variation between people
- Some medicines that act like dopamine, a brain chemical
- Less often: an underactive pituitary gland
What can throw it off
Stress, exercise, sex, breast stimulation and eating before the test can raise prolactin, and biotin, a hair-and-nail supplement, can distort some tests.
Questions to take to your appointment
- 1Could stress, exercise or my medicines explain this?
- 2Should it be repeated, and checked for macroprolactin?
- 3Is it high enough to need a scan of my pituitary?
Read together with
Doctors rarely read Prolactin alone. These usually sit next to it.
- TSHA brain hormone that tells the thyroid how hard to work.
- CreatinineA waste product from muscles that the kidneys clear.
- LHA brain hormone that triggers ovulation and drives testosterone in men.
- EstradiolThe main estrogen, a sex hormone made mostly by the ovaries.
- TestosteroneThe main male sex hormone, also made in smaller amounts in women.
Quick answers
What is the prolactin blood test?
Prolactin: A brain hormone best known for making breast milk. Prolactin comes from the pituitary, a small gland at the base of the brain. It drives breast milk after childbirth, and in anyone, too much of it can upset periods, fertility and sex drive. It is often checked when periods stop, when breasts leak milk outside of nursing, or when testosterone is low.
What is a normal prolactin level?
For most adults, prolactin is typically 4.8 to 23.3 ng/mL for women and 4 to 15.2 ng/mL for men. Some countries print it in mIU/L, so check the unit first. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high prolactin mean?
A mildly high prolactin is common and often comes from stress, exercise, a meal or some medicines. Much higher levels make a small, usually noncancerous pituitary growth (prolactinoma) more likely. Common reasons include stress, exercise, sex or breast stimulation before the test; pregnancy or breastfeeding; some medicines, including some for mental health, nausea or blood pressure; and macroprolactin, a large, mostly inactive form that some tests pick up. A doctor reads it together with your other results and how you feel.
What does a low prolactin mean?
A low prolactin is uncommon and rarely a concern on its own. It matters mainly if other pituitary hormones are low too. Common reasons include normal variation between people; some medicines that act like dopamine, a brain chemical; and less often: an underactive pituitary gland.
What can affect my prolactin result?
Stress, exercise, sex, breast stimulation and eating before the test can raise prolactin, and biotin, a hair-and-nail supplement, can distort some tests.
What should I ask my doctor about my prolactin?
Questions worth taking to the appointment: Could stress, exercise or my medicines explain this? Should it be repeated, and checked for macroprolactin? Is it high enough to need a scan of my pituitary?
What this page can’t do
It reads each number on its own.
Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.
It doesn't know you.
Your age, your medicines, how you feel and your last result all change what a number means.
It doesn't remember.
Close this page and your results are gone. That's on purpose: nothing was ever sent to us.
We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.
Vita: Health Coach on the App StoreSources
- Mayo Clinic Laboratories — Prolactin, serum
- Newcastle Hospitals Laboratories — Prolactin, serum
- MedlinePlus — Prolactin levels test
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.