Regulates hormones, progesterogenic, increase breast milk in nursing mothers. One of the most important herbs for regulating female hormones, chaste tree helps to balance progesterone and estrogen production, as well as inhibiting male androgens. Used to treat menstrual irregularities from premenstrual syndrome to absent or irregular periods. Tends to lengthen a short period and shorten a long one. Valuable in treating problems linked to the menstrual cycle, such as migraine and acne. Can help some women trying to conceive if infertility is due to low progesterone levels.