While some people colour their hair to cover their greys, others do so only because they like to experiment with new looks. No matter what your objective of colouring your hair is, you would have to use either a semi-permanent or permanent hair colour to change the appearance of your hair.

However many people are also concerned about the chemicals that hair colour contains. It’s true that certain chemicals cause skin irritation and allergies. Let’s take a look at what hair colour contains, whether you should be concerned and what you can do prevent it from affecting you.

The chemicals that hair colour contain

Hair colour contains hydrogen peroxide and ammonia. The hydrogen peroxide bleaches out the hair’s natural colour and releases oxygen; this allows the chemical reactions to take place. The other component ammonia breaks-down the hair-shaft’s outer cuticle and allows the chemicals to then enter the hair; this is the stage at which the hair development takes place.

These chemicals are pretty harsh and they also thin and harden the hair. Apart from that they may cause skin and eye irritation and they affect the respiratory system too. Some of the other irritants in hair colour include:


This may sometimes cause allergies & it can be irritating


This may be used as an alternative ingredient in ammonia-free products

Sodium lauryl sulfate (SLS)

This can irritate or dry your skin


These preservatives are generally questioned for their possible oestrogenic effects

Lead acetate

This is found in some hair colour restorers and not so much in hair colour.


This is a suspected carcinogen and a neurotoxin. Studies have shown that miniscule amounts get absorbed via the scalp, into the blood. However, not much is known about the cumulative effects of lead.

Allergy tests

Hair colour products have the potential to cause allergic reactions. If you have had a reaction to hair colour in the past, it’s best that you don’t colour your hair. The one way to minimise the risk is to perform a skin allergy test at least 48 hours before each application. This is how you go about it:

  • You would need cotton buds/cotton wool, a plastic spoon and a plastic bowl.
  • Mix very small equal parts of the colour developer and the colourant in the plastic bowl
  • Apply a very small amount of this mixture to the inside of your elbow and allow it to dry
  • Don’t wash the site for at least 48 hours
  • Examine the areas over the next 48 hours.
  • If you don’t notice any reaction, you can go ahead and use the colour
  • In case there is a rash/redness, or if any itching/burning occurs, you might be allergic to the product.


Use the remainder of mixture for a Strand Test

  • It’s important that you do the strand test every time you are going to colour your hair. This will help you determine the optimum colour results and timing
  • Previous colour, straightening and perms etc. can impact your timing and results
  • You will need a clock, scissors and some tape
  • Cut a ¼” strand right from the root area of the hair that’s typically not visible and then tape the strand, exposing the hair’s root end
  • Completely cover that exposed root end with the remaining colour mixture
  • Start timing
  • Post 10 minutes, check the root end of the hair strand. If it isn’t the colour you want, you can just leave the colour on for another 5 minutes


During the colouring process, if you experience any rash/burning/stinging, then you should rinse immediately. Don’t use any hair colour before you consult your physician. In case you experience any shortness of breath, it’s important that you seek prompt medical attention.

Thanks for reading,
Voila Hair & Beauty Team
(03) 9593 1260