Prolactin is a pituitary hormone that stimulates breast milk production.
- Normal range (adults)
- Men 2–18 ng/mL (42–382 mIU/L) · Women 2–29 ng/mL (42–615 mIU/L)
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Serum Prolactin, PRL, Prolactin Level, Lactogenic Hormone
Prolactin normal range
| Group | ng/mLConventional units: US, South Asia | mIU/LSI units: UK, Europe, Australia, international |
|---|---|---|
| Men | 2–18 | 42–382 |
| Women | 2–29 | 42–615 |
Prolactin is normally higher during pregnancy and breastfeeding.
Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.
Why is the Prolactin test done?
It is checked for irregular or absent periods, milky nipple discharge, infertility and low libido.
What does a high Prolactin level mean?
High prolactin can stop periods, cause breast discharge and lower fertility and libido. Stress and sleep before the test can raise it slightly.
Common causes
- Pregnancy and breastfeeding
- Stress, poor sleep or exercise before the test
- Medicines such as some antipsychotics, metoclopramide and domperidone
- Underactive thyroid
- Benign pituitary tumour (prolactinoma)
- Kidney disease
Diet and lifestyle tips
- Rest before the test; take it in the morning
- No specific diet; your doctor may check thyroid and repeat the test
When should you see a doctor?
A persistently high prolactin needs review; very high levels may need a pituitary scan.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.