Hair grows in 8-12 weeks after the end of chemotherapy for breast cancer, and the specific time is related to the growth cycle of hair follicle cells, personal nutrition, physical fitness and so on. When chemotherapy for breast cancer is given, as the chemotherapy drugs are not targeted, when killing the target tumor cells, it will also cause damage to other normal cells, such as hair follicle cells, making the hair follicles in the growth period enter into recession early, resulting in hair loss. The growth cycle of hair follicle cells is 8-12 weeks, and hair growth usually starts 8 weeks after the end of chemotherapy. When the end of chemotherapy for breast cancer, if the patient’s nutrition is sufficient and physical condition is good, usually in about 8 weeks the follicle cells can regenerate back to normal and can grow hair; if the patient’s nutrition is lacking, physical condition is poor and immunity is low, the time can be as long as about 12 weeks.