Breast tenderness certainly does not occur during menstruation or pregnancy, there is currently no such phenomenon and it is not scientifically justified. On the contrary, breast tenderness occurs after menstruation or after the end of pregnancy and breastfeeding. The breast consists of the ductal system, mammary glands, fat, lymph, veins and nerves. Normally, the breast is a soft tissue. Within the period of menstruation or pregnancy, drastic changes in the body’s hormones lead to an increase in the production of both estrogen and progesterone hormones that can promote the volume and texture of the breast. These hormones can cause the breasts to increase in size and become harder in texture. However, when menstruation stops or when pregnancy and breastfeeding end, the levels of these hormones drop dramatically, causing the glandular tissue of the mammary glands to lose the nourishment of the hormones and to become softer from its original expanded, harder texture. In addition, as a person ages, the female estrogen and progesterone secretion decreases, the breast tissue continues to undergo physiological atrophy, and the original breast tissue is gradually replaced or filled with fat tissue. Breast tissue will lose its original elasticity and texture, and the appearance is no longer presented as firm, which is a normal phenomenon of human aging. Therefore, most of the softening of the breast is a physiological change, the main reason for this change is due to changes in the secretion of human sex hormones.