Permanent dyes are also known as ‘oxidation’, this is because an ‘oxidizer’ (such as hydrogen peroxide) and ammonia are mixed with the colouring agent before application.
The formulation of permanent dyes is very complicated, and manufacturers go to great lengths to attain long-lasting colour that does minimal damage to the strength and elasticity of your hair. Because permanent dyes cannot be washed out, you may want to trial a new colour by using a semi-permanent or temporary dye before you use a permanent colour.
However, if your hair is bleached and you are thinking of going to a darker shade, it’s important to know that even temporary vegetable dyes can take quite a while to fully wash out. Unfortunately, temporary colours can’t be tried if you are thinking of lightening your hair, so a good option is to go into a high-end wig shop to test a new look.
Benefits of Permanent Dyes
Permanent dyes don’t have to be applied as often as semi-permanent or temporary colours and there is a wider range of permanent colour shades, which are often more natural-looking. Permanent dyes also encourage regular shampooing which supports a healthy scalp environment and in turn healthy hair.
Disadvantages of Permanent Dyes
Permanent dyes can be more damaging to your hair than semi-permanent or temporary dyes. The chemicals used are stronger and the mixture usually has to be left on for a longer period of time. Permanent dyes can’t be washed out if you’re unhappy with the colour. They can also cause allergic reactions.