Hair dye can cause skin allergies, leukemia and other diseases, because it contains a chemical called "p-phenylenediamine". Because the hair dye contacts the skin and is heated in the process of dyeing hair, benzene series organic matter enters the capillaries through the scalp after contact and heating, and reaches the bone marrow with blood circulation. If they repeatedly act on hematopoietic stem cells for a long time, it will lead to malignant transformation of hematopoietic stem cells and lead to leukemia. Therefore, the incidence of leukemia in people who dye their hair for a long time is definitely higher than that in people who don't.
Zhou, a senior engineer of Shanghai Institute of Quality Supervision and Inspection Technology, said that p-phenylenediamine is an internationally recognized carcinogen and its harm to human body has been widely recognized at home and abroad.
Foreign studies also show that people who often dye their hair will increase the incidence of breast cancer, skin cancer, leukemia and bladder cancer.
So in general, the love of beauty comes at a price. It is recommended to dye your hair no more than twice a year, and buy regular professional hair dyeing brands with guaranteed relative quality: L 'Oreal, Canil and Wen Ya, so as to reduce the risk, but it is not guaranteed to be absolutely harmless.