There is no absolute answer to the question of what day of menstruation is the most accurate for the six hormones, and the timing of the test should be chosen according to the purpose of the test. Sex hormones include follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), progesterone (P), testosterone (T), and prolactin (PRL), which can be used to understand a woman’s baseline endocrine level, assess her ovarian reserve function, and assist in the diagnosis of gynecological endocrine disorders, such as polycystic ovary syndrome (PCOS) and premature ovarian failure (POV). To assess the basic ovarian function, the test should be performed on the 2nd to 4th day of menstruation; to assess the luteal function, the test should be performed on the 21st to 22nd day of menstruation, 7 to 8 days after ovulation; if the menstruation is completely disorganized and irregular, and if it is necessary to determine the cause of the functional abnormal bleeding, blood can be drawn for the test at any time of the day. In conclusion, the time of blood collection for sex hormone 6 test varies according to the purpose of the test and should be performed under the guidance of a doctor.