High prolactin (hyperprolactinemia) can cause menstrual changes, amenorrhea, galactorrhea and infertility in women; low libido, erectile dysfunction, reduced sperm production and gynecomastia in men. It may reflect a prolactinoma, medications, hypothyroidism or chest stimulation. Diagnosis uses serum prolactin testing and pituitary MRI. Treatment addresses the cause—often dopamine agonists (cabergoline, bromocriptine), thyroid correction, or rarely surgery.

Prolactin is a pituitary hormone that promotes breast development and milk production after childbirth, supporting lactation and milk let-down. Elevated prolactin suppresses GnRH, reducing ovulation and menstrual regularity, which can cause amenorrhea and infertility. High levels may cause galactorrhea and lowered libido. It also influences maternal behavior and has minor roles in immune regulation and metabolism.

Prolactin is not typically elevated in PCOS, though mild increases can occur and the two conditions may coexist. Marked hyperprolactinemia is more often due to other causes (pituitary adenoma, medications, hypothyroidism) and can mimic PCOS symptoms. Clinicians routinely measure prolactin when evaluating oligomenorrhea or infertility to exclude alternative causes and guide management.

Normal prolactin depends on sex and pregnancy. Typical reference ranges: men about 2–18 ng/mL and non‑pregnant women about 2–29 ng/mL. Levels rise substantially during pregnancy (often roughly 100–400 ng/mL). Lab methods and units vary; results can be affected by timing, stress, and some medications, so discuss abnormal values with your clinician.

To lower high prolactin in women: see a doctor to identify the cause (pregnancy, hypothyroidism, medications, pituitary adenoma). Treat underlying conditions, stop or switch offending drugs, and use dopamine agonists (cabergoline or bromocriptine) if prescribed. Manage stress, maintain regular sleep, and undergo regular blood tests and imaging to monitor response and guide treatment.

Elevated prolactin (hyperprolactinemia) can contribute to weight gain in some people. High prolactin may increase appetite, promote fat storage and cause hypogonadism or thyroid changes that slow metabolism. Not everyone gains weight, and treating the underlying cause (for example with dopamine agonists or fixing thyroid dysfunction) often stabilizes or reduces weight. Lifestyle measures remain important.