Prolactin is a pituitary hormone that promotes lactation. It’s also involved in ovulation, orgasm, breast health, immune function, and mood. High prolactin is called hyperprolactinemia.
Symptoms of high prolactin include irregular periods or no periods, premenstrual mood symptoms, loss of libido, headaches, breast pain, vaginal dryness, acne, and hirsutism or facial hair. It’s one of several causes of excess androgens that can be mistaken for polycystic ovary syndrome or PCOS.