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Hair Dye with Ammonia: Does it Damage Your Hair?

When testing out different hair colours over the years I’ve tried out both hair dye with ammonia, and ammonia-free dyes. In this post I will explain the differences of each and why you might want to choose one over the other.

Hair Dye with Ammonia

Before we get into the differences between hair colourants with ammonia, and ammonia-free products, be aware that both of them contain harsh chemicals. Don’t be fooled into thinking that just because it’s ammonia free it won’t damage your hair. Any hair dye will weaken your hair!

People with sensitive scalps, or who have had a previous allergic reaction to ammonia may wish to opt for an ammonia free hair dye, but it isn’t necessarily the better choice. Although ammonia has been linked to hair damage, it will give you more vibrant color than its substitutes. It will also last longer on the hair, and be easier to rinse off.

In this post I will break down for you the reasons why ammonia is used in permanent hair dyes, what ammonia-free hair colour really means, and which would be the best choice for you.

The two articles that I mention in my video are the Olaplex Bonding Oil review and the list of cheaper alternatives to Olaplex.

Why is Ammonia Used in Hair Dyes?

Ammonia is a useful ingredient in hair dye. It is an alkaline chemical with a small molecule size, which means it can make the hair shaft swell and the hair cuticles open up. This makes it easy for hair dye to then be absorbed into the hair.

Our hair is naturally slightly acidic, and in order for hair dye to be absorbed into the hair it’s necessary to use an alkaline chemical. Alkaline chemicals change the pH level of the hair and open up the hair cuticles.

Ammonia is not only alkaline but also has small molecules which evaporate quickly. It’s the small molecules that make the hair shaft swell and become more absorbent to the dye. They also make the hair dye easier and quicker to rinse off.

Does Ammonia in Hair Dye Damage Hair?

Yes, if you are dying your hair frequently ammonia can weaken the hair strands. Since it causes the hair shaft to swell up and the hair cuticles to open, if you are dying your hair regularly, it can make the hair more porous in the long term. This means it will be more prone to breakage and frizz.

As well as potentially damaging the hair, ammonia has also been linked to skin irritation in sensitive individuals.

Despite this however there are still advantages to using ammonia in hair dye over its substitutes. It makes the colour brighter and more vibrant, and makes the dye last longer. Since ammonia is a small molecule it’s also easier to rinse off and less likely to leave behind residue.

Does Ammonia Make Hair Dye Last Longer?

Yes, compared to common ammonia substitutes, ammonia makes hair colour last longer. Ammonia makes the hair follicles swell which makes them much more absorbent. This then allows the dye to soak deeply into the hair. One of the main reasons ammonia is able to make the hair follicles swell so much is due to its small molecule size.

Ammonia free hair dyes use alkaline chemicals which have much larger molecules. These large molecules are less able to saturate the hair shaft than ammonia, and cause less hair swelling. This means they are less likely to damage the hair, but at the same time the dye cannot penetrate as deeply.

Whats the Difference Between Ammonia and Ammonia Free?

Ammonia has gained a bad reputation for causing damage to the hair, and this is why there are alternative hair dyes available which are labelled as “ammonia free”.

Although these dyes may be free from ammonia however, they still contain other alkaline chemicals which are similar to ammonia. Since it is hard to get the hair to absorb hair dye without an alkaline chemical, all hair dyes will contain something to alter the pH of the hair.

The most common substitutes for ammonia are monoethanlamine (MEA), and aminomethyl propanol (AMP).

These chemicals have much larger molecules than ammonia. This means they evaporate less quickly, and don’t give off such a strong smell. The large molecules however also mean that they are more difficult to rinse off the hair, and often leave residue behind. Ammonia free substitutes also won’t last as long or be as vibrant as hair dye with ammonia.

Ammonia free hair dyes are often marked on the front of the box with “No Ammonia”. The photograph below is an example of an an ammonia free semi-permanent color from L’Oreal.

Hair Dye with no Ammonia

Can You Get Permanent Colour Without Ammonia or Peroxide?

If you want a permanent colour that lightens the hair, you won’t find a product that doesn’t contain either ammonia or peroxide. There are some natural ways to lighten your hair such as using a chamomile tea rinse, vinegar, or lemon juice however the results are unpredictable.

If you already have light hair you may be able to use a natural hair dye like henna, but this may not show up on darker hair types. Natural hair dyes are also usually not permanent and will fade over time.

How Long Does Ammonia Free Hair Dye Last?

This depends on the condition of your hair, how often you wash it, and the hair dye you are using. There are some ammonia free hair dyes available which are permanent, however you may notice that the colour is less vibrant after around three months.

If your hair is in good condition, you wash it around 2-3 times a week, and you are using a permanent ammonia free dye (which usually contains hydrogen peroxide), your colour can last up to 14 weeks before it starts to fade.

From my personal experience I have noticed that the colour of both ammonia free and ammonia based dyes doesn’t last and will eventually fade.

I had my hair dyed several years ago with a permanent dye that contained both ammonia and peroxide. After around six months the blonde colour had become slightly ginger. When I tried an ammonia free permanent dye I noticed that the colour started to fade about two months earlier than when I had used the dye with ammonia.

Summary – Pros and Cons of Ammonia-Free Hair Color

The summary below sums up the basic differences you need to know between ammonia based and ammonia free hair dyes.

Hair Dye with Ammonia

  • Strong smell
  • Colour lasts longer
  • Quick and easy to rinse the hair dye out
  • Frequent use can lead to brittle and frizzy hair

Ammonia Free Hair Dye

  • No strong odour
  • Colour is less vibrant and won’t last as long
  • More difficult to rinse out and residue may be left behind
  • More gentle on the hair

You can get both semi permanent and permanent hair color that are free from ammonia. “No ammonia” dyes are considered better for hair health if you are going to be coloring your hair regularly to hide gray hairs.

Useful Articles

If you are interested in hair coloring using natural ingredients the following article lists a number of different options which include organic ingredients, and dyes containing emollient oils such as coconut oil. These might be a good option for you if you want to avoid ammonia due to scalp irritation or sensitive skin.


Does ammonia lighten hair?

Yes, hair dyes contain either ammonia or hydrogen peroxide to lighten the hair.

What is monoethanolamine in hair color?

Monoethanolamine (MEA) is often found in ammonia free hair dye. Like ammonia it alters the pH of the hair, but it is less volatile and damaging than ammonia. Hair dyes containing MEA are less likely to cause damage during the coloring process.

Do salons use ammonia free hair dye?

Yes! In 2010 L’Oréal brought in the first ever ammonia free permanent salon hair dye called the L’Oréal Professionnel INOA.

What's the difference between ammonia and ammonium hydroxide?

Ammonia becomes ammonium hydroxide when it reacts with water. They both work in hair dyes to alter the pH of the hair and prepare the hair to absorb the new colour.

This Post was All About Hair Dye with Ammonia

Thank you for reading my post about ammonia in hair dye. Remember that any hair dye will open up the hair cuticle and will make the hair more porous over time if you use it regularly. Coloring the hair too often has also been linked to hair loss so try to prevent the hair dye from touching your scalp if you can.