Prolactin (PRL) | LabsVault

What is Prolactin?

Prolactin is a hormone produced by the pituitary gland that primarily stimulates breast milk production after childbirth. It also plays roles in reproduction, metabolism, and immune function. Prolactin levels naturally fluctuate throughout the day and are influenced by stress, exercise, and sleep.

Why is it Tested?

Doctors order prolactin to investigate irregular menstrual periods, fertility issues, or unexplained breast milk production (galactorrhea). It’s also used to diagnose pituitary tumors, evaluate causes of erectile dysfunction, and monitor treatment responses.

Normal Ranges

Reference ranges vary by lab and sex. General adult guidelines:

Men: 4–15 ng/mL
Women (non-pregnant): 4–23 ng/mL
Pregnancy: Levels rise progressively, reaching 200+ ng/mL by delivery

Stress and time of day can significantly affect results.

Reference ranges vary by authority. Track yours across multiple standards with automatic unit conversions in LabsVault.

What do Abnormal Results Mean?

Abnormal results are not a diagnosis. Always discuss your results with a qualified healthcare provider before making any medical decisions.

Low Prolactin

Low levels are rarely clinically significant but may indicate:

Pituitary dysfunction
Certain medications
Rare genetic conditions

High Prolactin

Elevated prolactin may suggest:

Pituitary adenoma (prolactinoma)
Hypothyroidism
Medications (antipsychotics, antidepressants)
Stress, exercise, or nipple stimulation
Kidney or liver disease

How to Track Over Time

Prolactin levels can vary significantly day-to-day due to stress and other factors. Serial measurements help distinguish persistent elevation from temporary spikes. Tracking prolactin during treatment helps monitor medication effectiveness and adjust dosing for optimal outcomes.

Prolactin