Prolactin: what your level actually means
Also known as: PRL · Updated 19 Aug 2026 · Educational — not medical advice
The short answer: Prolactin is the pituitary hormone behind milk production, and levels are normally much higher in pregnancy and breastfeeding. Each lab sets its own normal range, which differs between methods and between men and women, so compare your result with the range printed on your report; the numbers on this gauge are only illustrative. Outside pregnancy, a high result is usually rechecked first, because stress, exercise or the blood draw itself can raise it, and then followed up for causes such as certain medicines, an underactive thyroid, kidney disease, macroprolactin (a large, mostly inactive form that lab tests still measure) or, less often, a small pituitary growth called a prolactinoma.
Where does your value sit?
This Prolactin value is inside the normal range. Your lab's printed reference range takes precedence — ranges vary slightly between laboratories.
What Prolactin tells you
Prolactin is a hormone made by the pituitary gland, a small structure at the base of the brain, and its best-known job is stimulating milk production after childbirth. Outside of pregnancy and breastfeeding, prolactin normally stays low, so persistently elevated levels in this setting usually prompt a search for an underlying cause. (Illustration is schematic.)
Common reasons it rises
- Pregnancy and breastfeeding — the expected, physiological reason for high prolactin in these situations.
- Certain medicines — many antipsychotics, some antidepressants, and a few blood pressure medicines commonly raise prolactin as a side effect.
- Hypothyroidism — an underactive thyroid can indirectly raise prolactin levels.
- Prolactinoma — a usually benign pituitary growth that overproduces prolactin, more often diagnosed once levels are quite high.
- Macroprolactin — a large, mostly inactive form of prolactin that most lab tests still measure, so a result can look high with no symptoms; the Endocrine Society suggests checking for it when high prolactin causes no symptoms.
- Stress or the blood draw itself — physical stress, including the stress of having blood drawn, can cause a temporary, mild rise.
And reasons it runs low
- Low prolactin is uncommon and usually not clinically significant on its own.
- Certain medicines, including some dopamine-related drugs, can lower prolactin as part of how they work.
Does food or exercise change this?
Check with your doctor first: Anyone on antipsychotic or antidepressant medicines, or with a suspected pituitary problem, should discuss an abnormal prolactin result with their doctor before assuming a cause.
General guidance for adults — not a personal diet plan. Your doctor or dietitian knows your full picture.
Checked against: MedlinePlus: Pituitary Disorders · Mayo Clinic: Prolactinoma
What to do next
Ask your doctor: “Could any of my current medicines be raising my prolactin level?”
Ask your doctor: “Should this be rechecked with a repeat, less stressful blood draw before we investigate further?”
Ask your doctor: “If this stays elevated, would you recommend pituitary imaging or a thyroid check next?”
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Questions people ask
Do I need to worry about a pituitary tumor if my prolactin is high?
Not necessarily — medicines and thyroid problems are more common causes of a mildly elevated prolactin than a pituitary growth. Doctors usually rule out these simpler explanations first and only pursue pituitary imaging if the level is notably high or other causes have been excluded.
Can stress really affect a prolactin test result?
Yes, prolactin can rise temporarily from physical or emotional stress, including anxiety about the blood draw itself, exercise, or even a recent meal. Because of this sensitivity, doctors often recommend a calm repeat test, usually taken three to four hours after waking, sometimes after fasting for several hours, before acting on a borderline result.
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