Women with menstrual disorders and infertility do not know when is the best time to have a sex hormone test? We recommend to have a blood test for sex hormone 6 (Luteinizing Hormone (LH) Follicle Stimulating Hormone (FSH) Prolactin (PRL) Testosterone (T) Progesterone (P) Estradiol (E2)) on an empty stomach on the 3rd-5th day of menstruation (menstrual period). This is because the hormone level at this time is the basal follicular phase and can truly reflect the basal level. However, for those who have not had a period for a long time and are anxious to know the results of the test, the test can be done at any time, and this time will be the premenstrual time by default? The results are then referred to the results of the luteal phase test. If it is to check the prolactin level, the blood should be drawn at 10-11 am after breakfast.