Follicular Stimulating Hormone (FSH) a reproductive hormone that is produced by the pituitary gland in the brain. FSH stimulates the growth and development of unfertilised eggs during the menstrual cycle in women and initiates the production of sex hormones such as oestradiol and progesterone. FSH is also used to stimulate the production of sperm in men. The FSH hormone is often tested with other sex hormones such as LH, testosterone, oestradiol and progesterone for diagnose infertility and pituitary gland disorders in men and women.