What does Ammonia do in Hair Colours?

Many people realise the term ‘No Ammonia’ in hair products typically means the item is kinder to the hair.  But do people know what ammonia does to the hair and when it is required?

The Science

Ammonia is an alkaline chemical that is used in hair colouring to open the cuticle and swell the hair shaft.  Ammonia will also increase activation of peroxide (which enables colour molecules to affix inside the hair). You can recognise ammonia (within a product) by a strong gas that is released when you open the colourant tube or bottle.

Negatives of Ammonia

Because ammonia opens the cuticle and swells the hair shaft (during colouring) it can, with continued use, cause the hair to become damaged and compromised. This continual swelling of the hair and opening of the cuticle can lead to cuticle damage, colour grabbing (and then colour fading) and a general decline in condition.

Positives of Ammonia

Ammonia does have many positives (when applied with understanding).  Stubborn white or grey hair benefits from an ammonia colourant to open the cuticle and allow full deposit of the colour.  Bleach also requires ammonia in order to lift the hair by anything more than 5 levels – which is the requirement of most blonde and highlight colourers.

Non ammonia based products are kinder to the hair, but remember they are far reduced in strength, so it’s harder to achieve dramatic results in a single application.  

Selecting a Non Ammonia Product

If you are looking to darken or create a tonal shade within your hair (and have no grey) a non-ammonia colourant could work well for you.   

Many people select shades (with ammonia) that are specifically designed for grey coverage.  If you are a serial colour swapper, it’s kinder (for your hair) to create your desired colour without the use of an ammonia colourant to do it.  Having a pre-lightened base and then using a non-ammonia colour can give you flexibility and retain your hairs health.

You should not apply an ammonia based colourant immediately after bleaching the hair or following application of a first ammonia based product.  If you apply ammonia twice in immediate succession the hair can over swell and become porous or damaged and ultimately give an inaccurate colour result and poor hair health.

When to Select an Ammonia Colourant

Significant grey coverage really benefits from the use of an ammonia active, because it opens the cuticle wide and deposits colour.  If you are looking to both lift and deposit a new colour an ammonia shade will also help achieve a desired result.  Ammonia colourants are also fine to use when changing shades after stripping.  Decolour Stripper (for example) contains no ammonia, so if the subsequent colour applied does contain the active, the hair will respond in a controlled manner and the colourant can deposit the new shade evenly on the hair. 

Remember, ammonia (in itself) is fine when applied with understanding to your hair type.  It’s the continued use (over previously treated areas of hair) which can lead to longer term problems.