About Prolactin
Prolactin is a hormone produced by the pituitary gland that drives milk production after childbirth but is present at baseline in all adults. Elevated prolactin (hyperprolactinemia) suppresses sex hormones — reducing testosterone in men and causing irregular periods or infertility in women — and can cause breast milk production outside of pregnancy in both sexes. The most common cause is a benign pituitary tumour called a prolactinoma; certain medications (antipsychotics, antidepressants, antiemetics) are another frequent trigger.