Kao foam hair dye belongs to temporary hair dye. Temporary hair dye is a kind of hair dye that can remove the color from hair only by washing it with shampoo once. Because the particles of these hair dyes are large, they can not enter the hair shaft through the epidermis, but can only be deposited on the hair surface to form a colored covering layer. In this way, the interaction between dyes and hair is not strong, and it is easy to be washed off by shampoo.
It is worth noting that hair dyes are generally not used for more than half a year after opening a bottle, and the interval between two hair dyes is more than 3 months. Don't use different brands of products at the same time, because chemical reactions may occur between them, producing toxic substances and increasing the probability of allergies.
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Experts suggest that you should not dye your hair more than twice a year. Patients with hypertension, heart disease and asthma should not dye their hair. In addition, couples who are ready to give birth, pregnant women and lactating women are not suitable for dyeing their hair.
Long-term use of hair dye is harmful to health. American experts examined 160 popular hair dyes, and found that 150 of them had carcinogenic effects. For example, in oxidized hair dyes, there is a substance called 2-4 amino anisole, which is most likely to accumulate in the human body and promote cell proliferation. In general, if the hair dye is used for 10 years, human skin can cause cancer as long as it absorbs 1% of this substance.
In addition, the use of hair dye will make the immune function of human body disorder, which will lead to lupus erythematosus. Other hair dyes can cause allergic dermatitis and allergic conjunctivitis. Therefore, scientists warn people that hair dyes should be used with caution.
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