Prolactin

High prolactin can disrupt sex hormones and fertility. Women may get irregular periods or stop menstruating, infertility, and milky nipple discharge; men can have low libido, erectile dysfunction, and infertility. Chronic high prolactin causes low estrogen/testosterone, increasing osteoporosis risk. Large pituitary tumors may cause headaches and visual field loss. Treatment depends on the cause and can reverse many effects.

Prolactin is a hormone produced by the anterior pituitary that stimulates breast development and milk production (lactation). Levels rise during pregnancy and breastfeeding. It also affects reproductive function by modulating gonadotropin-releasing hormone, so elevated prolactin can cause menstrual irregularities, reduced fertility, and galactorrhea. Abnormal levels warrant medical evaluation to determine cause and treatment.

Prolactin is not typically elevated in polycystic ovary syndrome; most people with PCOS have normal prolactin levels. Mild hyperprolactinemia can coexist in a subset, so an elevated prolactin warrants evaluation for other causes (prolactinoma, hypothyroidism, medications). Clinicians recommend testing when symptoms suggest hyperprolactinemia (galactorrhea, amenorrhea, infertility); treatment targets the underlying cause.

Normal prolactin levels in adults are roughly: non‑pregnant women about 4–23 ng/mL and men about 3–15 ng/mL. During pregnancy prolactin rises substantially, commonly into the 30–400+ ng/mL range. Results may be reported as ng/mL or mIU/L (1 ng/mL ≈ 21.2 mIU/L). Lab-specific reference ranges vary, so review results with your clinician.

Reduce prolactin by treating underlying causes: normalize thyroid function, review and stop prolactin‑raising drugs, and address pituitary adenomas with dopamine agonists (cabergoline, bromocriptine) or surgery if needed. Also reduce stress, improve sleep, avoid nipple stimulation, and lose excess weight. Medication review should target antipsychotics, metoclopramide and opioids as possible contributors.

Elevated prolactin (hyperprolactinemia) is associated with weight gain in some people. High prolactin can increase appetite and alter metabolism, and lowered sex hormones from prolactin excess may reduce muscle and increase fat. Certain medications that raise prolactin also cause weight gain. Treating the underlying cause often helps, but not everyone with high prolactin gains weight.