Does hair dye damage your hair?

Hair coloring is one of the most common salon services throughout the world, but as common as the use of hair dye is, did you know that it still may not be 100% good for your hair?


What are hair dyes?

Hair dyes are chemical coloring agents which bind with individual hair strands to apply the new chosen hair color. 

Generally, hair dyes are classified into four types.

  • Temporary hair dyes

As the name suggests, these hair dyes are non-permanent and come off as soon as the hair is washed. Temporary hair dyes are available in the form of rinses, gels, mousses and sprays.

  • Semi-permanent hair dyes

These hair dyes bind with the hair shaft, last longer than temporary dyes, and do not get rinsed off immediately after coming into contact with water. Semi-permanent hair dyes are available in the form of liquid, gel and aerosol. 

  • Permanent hair dyes

As the name suggests, these dyes are everlasting. They not only bind to the hair shaft, but also penetrate into its roots. 

  • Gradual hair dyes

These dyes are applied daily for a few days or a week until a shade darker than the original hair color is achieved. 



The negative side of hair dye: Ammonia and Peroxide

Hair dyes are made with chemicals, meaning that when they’re applied, several chemical reactions take place in order to allow the dye to bind with the hair shaft and penetrate deeply into the roots. The two most notorious ingredients found in hair dyes are ammonia and peroxides. 

Hair is made up of three layers: the cuticle, the cortex and the medulla. The cuticle is the outermost layer which acts as the protecting shield, keeping the hair safe from any damage. The pigment which gives your hair its original color lies beneath the cuticle, meaning that for a dye to reach the original pigment and overlap it with the new desired color, it needs to penetrate the cuticle. 

This is where ammonia comes into action. Ammonia in fact lifts up the cuticle and creates a passage for the dye to enter without any barrier, and as soon as the chemical penetrates through the cuticle, damage to the hairs’ natural state, inevitably occurs. Even though the cuticle goes back to its original position once the hair is rinsed, the damage done by the dye may still result in hair breakage

In addition to the damage done by ammonia, peroxide, the chemical responsible for the desired hair coloring, contributes to making your hair frizzy and weak. Consequently the hair shafts become very brittle and fragile, once again becoming prone to breaking at any point along the entire length. 


Ammonia-free hair dyes any better? 

So, if ammonia damages hair, are ammonia-free hair dyes any better? Unfortunately no, they are not. As previously explained, ammonia’s function in dyes is to lift the cuticle so that pigment can settle inside the hair strand. In ammonia-free hair dyes monoethanolamine (MEA) serves the same purpose. The only difference between the two chemicals is that MEA exists in the liquid form instead of the gas form, but nevertheless, by penetrating into the hair, it still risks causing damage and aiding hair breakage.


  1. HealthCentral. (2019, March 30). What are Hair Dyes? Retrieved August 25, 2020, from
  1. Komar, M. (2019, August 22). What Hair Dye Actually Does To Your Hair, According To Science. Retrieved August 25, 2020, from