The causes of yellowing and thinning hair are also divided into congenital and acquired differences. The congenital yellowing and thinning of hair is determined by genetics and the difference of human race, there is no good way to treat it, the acquired yellowing and thinning of hair is mostly caused by diseases, such as hypothyroidism, high malnutrition, severe iron deficiency anemia and the first recovery from a serious illness, etc., can lead to a decrease in the synthesis and secretion of melanin by melanocytes in the body, so that the basic material of black hair is lacking, resulting in hair from the original The hair will gradually change from black to yellowish brown or yellowish, and it will be easy to lose hair and cause thinning hair. In addition, improper maintenance of hair, often perm and hot blow dry, washing hair with laundry detergent and alkaline water, over time to damage the hair, resulting in yellow hair, damage to the hair quality, causing hair loss phenomenon. What are the causes of yellowing and thinning hair? 1, the factors of heredity. 2, heavy iron deficiency anemia and major illness, etc., resulting in a decrease in melanin in the body, so that the lack of basic substances of black hair, black hair gradually become yellowish brown or yellowish. 3.Highly malnutrition. Malnutrition is due to insufficient energy and/or protein intake, resulting in poor nutritional status or inability to maintain normal growth and development. Individuals will be malnourished if they are unable to consume a healthy diet consisting of the appropriate amount, type or quality of nutrients over a long period of time. Chronic malnutrition may lead to death by starvation. 4, frequent perming, shampooing with lye or laundry detergent can also cause hair damage and yellowing. Perm is a hairdressing method, and now the most used is chemical perm. The process of perming can cause damage to the scales on the surface of the hair. Make the internal structure of the hair in an unprotected state, will make the internal water and nutrients loss, harmful to the hair, scalp and hair follicles, will more or less make the hair cortical layer within the protein fiber tissue degeneration, so that the hair hair stiff, brittle, no light, dry, easy to yellow, brittle, easy to fall off, no luster, no elasticity. 5.Low thyroid function. At the stage of mucinous edema, it will manifest as thinning hair, dry and easy to fall off, ciliary and eyebrow hair loss.