Question: Why is hair colour bad for your hair?

Amy Evans answered on 22 Jun 2012:

Hi ameliarose

The two main chemical ingredients involved in hair colouring are Hydrogen peroxide and Ammonia. These chemicals can be harsh and harmful to your hair but it does depend on the type of colour you put on the hair.

Hydrogen peroxide helps to start off the colour-forming process and creates longer-lasting colour. Hydrogen peroxide causes sulphur to be removed from the hair and this loss of sulphur causes hair to harden and lose weight.

Ammonia is an alkaline chemical that enables hair lightening by speeding up the reaction between the hydrogen peroxide and the hair. Ammonia tends to separate the cuticle and allow the hair colour to penetrate the cortex of the hair.

semi-permanent colourings contain tiny colour molecules that enter the hair’s cuticle, (the outer layer) and go into your hair’s cortex. They don’t interact with your natural hair colouring. As the molecules are small, they eventually get out of the hair shaft after a few shampoos, leaving the hair as it was before treatment. This hair colouring contains no ammonia or peroxide.

Permanent colour – For more significant and long lasting colour change, both ammonia and hydrogen peroxide are used. Tiny molecules enter all the way into the cortex, where they react and expand to a size that cannot be washed out. These colours lighten the hair’s natural colour to form a new ‘base’ and then to add a new permanent colour.