Which hormone stimulates milk production in the breasts during lactation?

Prolactin is the hormone primarily responsible for stimulating milk production in the breasts during lactation. Released by the anterior pituitary gland, prolactin promotes the growth of mammary glands and stimulates the production of milk in response to suckling. This process is crucial for feeding infants and ensuring proper nutrition early in life.

While oxytocin also plays a role during lactation, its main function is to stimulate milk ejection or let-down reflex rather than the production of milk itself. Estrogen and progesterone are hormones that help prepare the breasts for lactation during pregnancy, but they are not directly involved in stimulating milk production after childbirth. Thus, prolactin stands out as the key hormone triggering the creation of milk in the postpartum period.