What is a normal prolactin level?

Bottom lineA normal prolactin level for a non-pregnant woman is usually under about 25 ng/mL, though lab cutoffs vary between roughly 15 and 25; men run under about 20, and pregnancy or breastfeeding levels of 80 to 400 ng/mL are normal. Above the range, 20 to 50 may only shorten the luteal phase, 50 to 100 often disrupts or stops periods, over 100 usually stops them, and over about 200 strongly suggests a prolactinoma. Because sleep, stress, exercise, sex, and breast exams spike prolactin, a mildly high result should be repeated before it is acted on.

For a woman who is not pregnant or breastfeeding, a normal prolactin level is usually under about 25 ng/mL. Exact cutoffs vary by laboratory - many use an upper limit somewhere between 15 and 25 ng/mL - so always read your result against the range printed on your own report.

Typical ranges

• Non-pregnant women: under roughly 25 ng/mL
• Men: under roughly 20 ng/mL
• Pregnant or breastfeeding: roughly 80 to 400 ng/mL, which is 10 to 20 times baseline and completely normal

What the number suggests

Above the normal range, the level gives a rough steer on both symptoms and cause:

• 20 to 50 ng/mL - may only shorten your luteal phase
• 50 to 100 ng/mL - periods often become infrequent or stop
• Over 100 ng/mL - periods usually stop altogether
• Over about 200 ng/mL - strongly suggests a prolactinoma, a benign pituitary tumor, since most other causes rarely push levels that high

One high result is not a diagnosis

Prolactin spikes with sleep, stress, pain, exercise, sex, nipple stimulation, and even a recent breast exam. A mildly elevated result should be repeated before anyone acts on it, because these often come back normal.

Two lab quirks matter too. Macroprolactin is an inactive form that reads high on the test but does nothing in the body - worth asking about if your level is high but you have no symptoms. The hook effect is the reverse: a very large tumor can overwhelm the assay and read falsely low.

More detail in prolactin in women and why prolactin is high in non-pregnant women.

Track your cycles in Femora so a borderline result can be read alongside what your periods are actually doing.