Prolactin test for men: why it is checked and what it shows

Prolactin is best known as a hormone for breastfeeding, so it surprises many men to see it on a hormone order. It is made by the pituitary gland in everyone, and in men it is normally low. A high level can be one reason testosterone is low or sex drive has dropped.

Prolactin

A single prolactin test, which checks one pituitary hormone and costs less than a hormone panel.

$59

See this test at HealthLabs

Price checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.

What the test measures

Prolactin is made by the pituitary gland, a small gland at the base of the brain. Its main role is to prepare the breasts for milk production. Levels are normally low in men and in women who are not pregnant (MedlinePlus).

Why it is checked alongside testosterone

The Endocrine Society’s guideline lists high prolactin as a cause of secondary hypogonadism, meaning low testosterone that starts in the pituitary or hypothalamus rather than the testicles. It says clinicians should measure prolactin in men found to have secondary hypogonadism, as part of looking for the cause (Bhasin et al., 2018). That is why prolactin often appears next to testosterone and LH. See LH and FSH in men.

Who might consider it

MedlinePlus says men may be tested for symptoms that high prolactin can cause. These include nipple discharge, erectile dysfunction, enlarged breasts, less facial and body hair, and low sex drive. The test is also used to help find the cause of male infertility.

If you have these symptoms, a clinician should be part of the process. A self-ordered prolactin test can show you a number, but it cannot examine you or look for a cause.

How to prepare

• Timing. Prolactin varies during the day. MedlinePlus says the sample is usually taken three to four hours after you wake up.
• Fasting. MedlinePlus says your provider may ask you to fast for several hours. The seller’s page says fasting is not required, but that wording is shared across its single-test pages. Follow the instructions on your lab order.
• Medicines. Some medicines and vitamins can affect results. Tell the person drawing your blood about all of them. Don’t stop any medicine unless your provider tells you to.

If you are also testing testosterone, the Endocrine Society guideline describes a morning sample. Ask which timing applies to your order and see best time to test.

What the seller’s test includes

The seller’s page describes this as a prolactin-only test. It says the test doesn’t include LH, FSH, TSH or other pituitary hormones. If your question needs those, you would order them separately.

What a result can and can’t tell you

Labs set their own ranges, so use the range printed on your report.

• Higher than the range may be linked to a prolactinoma (a pituitary growth), other pituitary disorders, hypothalamus disease, an underactive thyroid, cirrhosis or kidney disease.
• Lower than the range is rare and may point to a pituitary disorder.

MedlinePlus is plain about the limits. A prolactin test can’t show the cause of a high level, and “higher-than-normal prolactin levels don’t always mean you have a medical condition that needs treatment.” Diets high in protein and certain medicines can cause high levels, and small rises can come from stress, exercise or sex. Providers may retest to see whether a level stays high, and usually order other tests to look for a cause.