Why does hair fade after dyeing?

1) Shampoo

Studies have shown that shampoo surfactants have a fading effect on the color of hair after dyeing. And even if you just wash your hair with water, after 10 or more washes, your hair will start to look faded.

(2) Optical damage

Under normal circumstances, after 8-10 hours of cumulative exposure to sunlight, dyed hair will begin to fade slowly. Hair dyes are sensitive to ultraviolet light, especially UVA, and these dye molecules react with sunlight and gradually lose their original color.

3) High temperature

Hair dyes are easily degraded at high temperatures, so prevent the hair from being exposed to a high temperature after dyeing. For example, avoid using the hair dryer too close or the water temperature when shampooing is not too high.

Therefore, the general idea of color protection products is: internal repair + external isolation

Note: Color protection shampoo is mainly to slow down the speed of hair color fading. It cannot make the hair dye not fade completely. It can only slow down and maintain the color of the dyed hair as much as possible.