It is best not to wash your hair the day before dyeing your hair. If you want to wash your hair, you'd better wash it two or three days before dyeing it. This is because the principle of dyeing hair is to open the hair scales on the surface of the hair and let the dyed color particles enter the hair smoothly. Scalp is the densest place of human hair follicles, and harmful substances of hair dye can easily enter the human body through hair follicles. Even if the hair dye is not in direct contact with the scalp, it will volatilize to form gas and enter the body. Therefore, scalp grease should be used to resist these harmful substances, and do not wash your hair to wash off these grease protective layers before dyeing your hair.

You can wash your hair 2~3 days before dyeing your hair. When washing your hair, it is best to massage gently with your fingertips to avoid scratching your scalp with your nails to avoid damage. When dyeing hair, the ingredients in the hair dye will irritate and cause scalp allergy.

Extended data

Hair dyeing is one of the most common means of modern makeup, which uses plants (such as avocado, henna, Polygonum multiflorum, etc. ) or chemical pigments to dye the hair in the desired color. This is one of the most common services in modern barber shops.

There are two main uses of hair dyeing: one is to dye black to cover white hair; Second, for the sake of fashion, change the color of hair with the mood, cooperate with clothing and makeup, and fully show your personality. Dyeing hair has become a fashion. Young people can change the color of black hair with their moods, and fully display their personalities with their clothes and makeup. Middle-aged people have to dye black frequently because they keep growing white hair.

2065438+071October 27 17 The list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization was preliminarily sorted out for reference. Hair dyeing products (personal use) are included in the list of three types of carcinogens. Baidu encyclopedia-hair dye