Hair dyes are used to change hair colours. Hair dyes may be made of natural ingredients or synthetically derived.

How do hair dyes work?

1. Synthetic hair dyes
*They are hair dyes with chemicals which open up the cuticle scaleson the outside of the hair shaft.
*The cuticle scales slose again after processing
*If the hair is processed too often, the cuticle does not close as tightly and the hair shaft becomes
very fragile.

2. Natural hair dyes
* The hair dyes with natural ingredient, however coat the outer scaly layer of the hair shaft instead of
penetrating the hair shaft.
* The natural pigments of the hair shine through the colour layer,thus the new hair colour is the resultant of the combination of the original colour and the applied hair colour layer.

Hair dyes Treatment

There are basically three types of hair dyes as listed below:
1. Temporary hair dyes
*They are in the forms of gels, mousses, sprays and rinses.
*They simply stay on the surface of the hair.
*They are washed out with the next shampoo, therefore they need to be re-applied after each shampooing.

2. Semi permanent dyes
* They are in the forms of liquids, gels, or aerosols
* Their molecules are smaller than those of temporary hair dyes.
* They penetrate into and adhere to the hair shaft.
* They are usually applied daily until a dark enough shade is achieved, after which it may be used less
often to maintain the colour.
* They do not wash off readily or run when hair gets wet.

3. Permanent dyes
*They require more work to apply but the hair colour lasts until the new hair roots grown in.
*They usually contain hydrogen peroxide, therefore they cover grey hair more effectively and can be usedto lighten hair colour unlike other dyes.
*They penetrate deeply into the hair shaft and get locked within it due to a series of chemical reactions that occur while the dye is applied.
*They generally cannot be washed out with shampoo, however repeated shampooing may reduce the colour overtime.

Ingredients in hair dyes
They are basically plant derived such as henna, or synthetically derived like coal tar or petroleum. Take extra caution when choosing hair dyes as some may contain substances harmful to users.