Prolactin: What Your Result Means
Result guide · Hormones
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
Prolactin is the milk-production hormone. High levels can suppress sex hormones and cause missed periods, low libido, or breast milk when not breastfeeding. Modest elevations are often stress-related or benign.
What is Prolactin?
Prolactin is released by the pituitary gland. It enables breastfeeding and regulates reproductive function. Because it is sensitive to stress, sleep, exercise, and even the blood draw itself, mildly elevated values are common and often meaningless; large sustained elevations point to a pituitary issue.
Typical reference interval: Normal for non-pregnant, non-nursing adults is broadly under 20–25 ng/mL. Pregnancy and breastfeeding raise levels dramatically. Different assays vary, so rely on your lab's printed range.. Laboratories differ — the interval printed on YOUR report always governs.
If your Prolactin is high
Common reasons Prolactin runs above the reference interval:
- Pituitary tumor (prolactinoma) — the classic cause of a high, sustained elevation — usually treatable
- Pregnancy and breastfeeding — physiologic and expected
- Stress, exercise, or recent sleep changes — prolactin is a stress hormone — transient rises are normal
- Certain medications — antidepressants, anti-nausea drugs, some blood-pressure and acid-suppression drugs can raise it
- Kidney or liver disease — reduced clearance can elevate prolactin
- Hypothyroidism — high thyroid-stimulating hormone can stimulate prolactin release
If your Prolactin is low
Common reasons Prolactin runs below the reference interval:
- Pituitary dysfunction — rare; a low value with other pituitary-hormone deficits may point to pituitary insufficiency
- Certain medications — dopamine-based drugs can suppress prolactin
Symptoms worth knowing
High prolactin: missed or irregular periods, breast milk production without pregnancy (galactorrhea), low libido, erectile dysfunction in men, and sometimes headaches or vision changes if a tumor is present. Low prolactin is usually asymptomatic.
What usually happens next
Get your Prolactin checked
These lab tests measure Prolactin directly. Ordering online takes a few minutes and results arrive securely.
We may earn a commission when you order through partner links on the following pages. Educational information here never replaces advice from a qualified healthcare provider.
Panels that include this value
Prolactin appears as one line inside these broader panels — better value than ordering single markers alone:
Related result guides
Frequently asked questions about Prolactin results
My prolactin is 30 and the range tops out at 25 — is that a tumor?
Very unlikely. Mild elevations are usually stress, sleep, medication, or timing. A true prolactinoma typically produces much higher values, and only a persistently high result with symptoms warrants imaging.
Do I need to fast for a prolactin test?
Fasting is not required, but timing matters — draw in the morning, ideally 2–3 hours after waking, after a normal night's sleep and minimal stress, because prolactin spikes with activity.
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