Prolactin optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Prolactin, which differ for men and women:

Female: Optimal 5 – 20 ng/mL (5 – 20 μg/L); sufficient 4.8 – 23.3 ng/mL (4.8 – 23.3 μg/L); out of range below 4.8 or above 23.3 ng/mL.
Male: Optimal 4 – 15 ng/mL (4 – 15 μg/L); sufficient 4 – 15.2 ng/mL (4 – 15.2 μg/L); out of range below 4 or above 15.2 ng/mL.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

Unit	Applies to	Optimal	Sufficient	Out of range
ng/mL	Female	5 – 20	4.8 – 23.3	below 4.8 or above 23.3
ng/mL	Male	4 – 15	4 – 15.2	below 4 or above 15.2
μg/L	Female	5 – 20	4.8 – 23.3	below 4.8 or above 23.3
μg/L	Male	4 – 15	4 – 15.2	below 4 or above 15.2
mIU/L	Female	106 – 424	102 – 494	below 102 or above 494
mIU/L	Male	85 – 318	85 – 322	below 85 or above 322

What the evidence says

The bands are a laboratory reference interval for adults: 4.8 to 23.3 ng/mL in women and 4.0 to 15.2 in men (Mayo Clinic Laboratories). Other laboratories print higher upper limits, up to about 33 in women and 31 in young men, so a mildly raised result should be read against the report's own range. The narrower optimal bands are functional targets; no narrower target is published. Prolactin is only mildly cycle-dependent but rises with stress, sleep, exercise and nipple stimulation, with many medicines (antipsychotics, some antidepressants, metoclopramide, opiates, oestrogens), and is greatly elevated in pregnancy and breastfeeding. For a baseline, test in the morning, rested and not after exertion, and repeat a mildly raised result. These ranges are informative, not diagnostic.

For women: This is an informative female reference range, not diagnostic. Prolactin is only mildly cycle-dependent but rises with stress, sleep, exercise, and nipple stimulation, and is greatly elevated during pregnancy and breastfeeding. For an accurate baseline, test in the morning, rested, and not after exertion.

Sources

Prolactin, Serum (PRL) — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceAdults aged 18 and over: men 4.0 to 15.2 ng/mL, women 4.8 to 23.3 ng/mL. Macroadenomas are typically associated with concentrations above 250 ng/mL.
Prolactin (test 004465) — Labcorp, 2026 · Laboratory / reference-interval sourceWomen 4.8 to 33.4 ng/mL from 13 to 50 years and 3.6 to 25.2 at 51 to 80; men 3.6 to 31.5 at 13 to 30 and 3.9 to 22.7 at 31 to 50. Shows that upper limits differ by laboratory and age: the female lower limit of 4.8 agrees with Mayo, the upper limits do not.

What Prolactin measures

A hormone best known for driving milk production.

High prolactin can cause irregular periods, headaches, and fertility problems.

Related hormone health markers

See Prolactin in the full list of biomarker ranges

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.