Luteinizing Hormone (LH)

Luteinizing hormone (LH) is a reproductive hormone produced by the pituitary gland that normally surges mid-cycle to trigger ovulation and egg release, and also stimulates the ovaries to produce androgens. In PCOS, LH levels are persistently elevated—often 2-3 times higher than normal—due to abnormal GnRH (gonadotropin-releasing hormone) pulsing and insulin resistance, which drives excessive androgen production from ovarian cells and disrupts the delicate hormonal coordination required for normal ovulation. This chronically high LH, combined with relatively low FSH, contributes to the follicle arrest and accumulation of immature follicles that characterize polycystic ovaries.