The "Kidney" meridian in TCM includes functions of the actual kidneys as organs from a Western perspective, but also encompasses adrenal and reproductive health. The Kidney meridian as a whole is thought of as the “battery” of the body, governing vitality, and Kidney “Yin” specifically refers to this meridian’s role in governing healthy fluids throughout the body.
You can think of your “yin” as your juiciness or your body’s lubrication; it’s related to healthy estrogen levels (since estrogen is related to water balance), mucus and endometrial health, and your sense of nourishment, all of which are important for normal, healthy fertility. Herbs like Red Clover are included in this formula to support our “yin” and thus support healthy, normal follicles, healthy hormone levels, and more.*