The normal range of follicle stimulating hormone is usually 5-40mIU/mL. follicle stimulating hormone is a glycoprotein hormone secreted by basophilic cells of the anterior pituitary gland, and its main function is to promote follicle development and maturation. fsh varies somewhat in the middle of the menstrual cycle, rising during ovulation and decreasing after ovulation. So FSH is normally between 3.5-12.5 IU/L during follicular phase, 4.7-21.5 IU/L during ovulation, 1.7-7.7 IU/L during luteal phase, and 25.8-134.8 IU/L during menopause. However, a FSH higher than 12 IU/L indicates poor ovarian function and higher than 20 IU/L indicates premature ovarian failure which can lead to infertility. The time of follicle stimulating hormone test should be more accurate between the 2nd and 4th day of menstruation.