- Made by
- The pituitary gland
- Most common disease cause of high levels
- Prolactinoma (benign pituitary tumor)
- Best timing
- About 3 to 4 hours after waking
- Usual first treatment for prolactinoma
- A dopamine agonist, such as cabergoline
Why prolactin affects sex hormones
Prolactin levels are naturally high in pregnancy and while breastfeeding, and that high level helps pause ovulation. When prolactin is high for other reasons, it can interfere with the brain hormones that drive LH and FSH, which lowers testosterone in men and estrogen in women.
That is why the American Urological Association recommends a prolactin test in men with low testosterone whose LH is low or low-normal.
Symptoms of high prolactin
- Men: low sex drive, erectile dysfunction, breast enlargement, nipple discharge and less body hair.
- Women: irregular or absent periods, infertility, low libido and milky nipple discharge when not breastfeeding.
- Either sex: headaches or vision changes if a pituitary tumor is large enough to press on nearby structures.
Common causes
- Prolactinoma, a usually benign pituitary tumor.
- Medications, including some antipsychotics, antidepressants, anti-nausea drugs and opioids.
- Hypothyroidism and kidney disease.
- Temporary bumps from stress, exercise, sex, a stressful blood draw or a high-protein meal.
- Macroprolactin, a large inactive form that can make results look high without causing symptoms.
Testing well
Prolactin varies through the day, so MedlinePlus advises drawing the sample about 3 to 4 hours after waking. The Endocrine Society's guideline says a single clearly elevated result drawn without undue stress can confirm the finding, and recommends ruling out medications, kidney failure, hypothyroidism and pituitary or nearby tumors as causes.
Mild elevations are frequently repeated. Never stop a prescribed medicine to test prolactin without talking to the prescriber, especially psychiatric medicines.
Treatment
Treatment depends on the cause. A medication-related rise may be managed by switching drugs where safe. For a symptomatic prolactinoma, the Endocrine Society recommends a dopamine agonist, preferring cabergoline, with surgery reserved for cases that do not respond. Thyroid treatment resolves rises caused by hypothyroidism. A HealifyMD clinician can order prolactin as part of a hormone work-up and refer you to an endocrinologist when imaging or specialist care is needed.
Why it matters in midlife
Low libido, erectile changes and irregular periods are common after 40 and usually have ordinary explanations. Prolactin is one of the less common but very treatable causes, and it is easy to miss if only testosterone or estradiol is checked. Because many midlife adults take antidepressants, acid reducers or pain medicines, reviewing the full medication list is an important part of interpreting any high result.
Prolactin: common questions
Can high prolactin cause low testosterone?
Yes. It can suppress the brain signals that tell the testes to make testosterone, which is why it is checked in some men with low T.
Do men make prolactin?
Yes, at low levels. Its role in men is less clear, but abnormally high levels cause symptoms.
Is a prolactinoma cancer?
Almost always no. Prolactinomas are typically benign and often respond well to medication.
Should I fast before the test?
Some labs request a few hours of fasting. Follow your lab's instructions and avoid strenuous exercise beforehand.
Can stress make my result high?
Yes, temporarily. That is one reason borderline results are often repeated.
Will treating high prolactin restore my libido?
Correcting the cause often improves hormone levels and symptoms, though results vary and other factors may also play a role.
Sources
We cite government agencies, professional societies and peer-reviewed research. See our editorial policy.
- Prolactin levelsMedlinePlus (U.S. National Library of Medicine)
- Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline (2011)Endocrine Society
- Evaluation and Management of Testosterone Deficiency guidelineAmerican Urological Association