Can I mix a 10 and a 20 volume developer? I don’t recommend it!

hairdresser mixing developer and dye in a bowl

  • Mixing 10 and 20 volume developers isn’t a good idea.
  • The result will be a 30 volume developer. It’ll cause a strong chemical reaction that will ruin your hair color or severely damage it.
  • Mixing different volumes of developers requires specific knowledge in coloring.


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To make it clear:  as a professional stylist, I don’t recommend mixing a 10 and a 20 volume developer. 

The volumes of developers add up, and the result will be a 30 volume developer. It can be strong enough to damage your hair or, at least, cause uneven and unwanted color.

Don’t you believe me?


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Let me tell you the story of Victoria, one of my clients, who likes to change her hair color quite often.

A few months ago, I was in the salon setting up new products when a woman came in with red hair and carrot-orange roots.

At first glance, I didn’t recognize her. When I got closer, I couldn’t believe my eyes: it was Victoria!

But what had happened to her ashy dark blonde color, which I had applied only two weeks before?


When she sat down on the couch, she was very embarrassed and told me the story.

A coworker showed her a model on Instagram with dark red hair.

Victoria fell in love with the color.

When she got home from work, she went to the store and bought only the hair dye. She had a 20-volume developer at home.


When she began to prepare the mixture, she realized that  the 20-volume developer wouldn’t be enough for the mixture. 

So, she decided to add a 10-volume developer.


After rinsing out the dye, she looked at her hair in horror.

Her roots had turned a lighter color, to be more precise, a carrot orange. The rest of her hair was a bright brassy fire red.

Why did she have that difference in color in her hair?


 If you mix a 10-volume with a 20-volume developer, what you get is a 30-volume developer. 

And that 30-volume developer produces a stronger chemical reaction than the 20-volume one.


The developer mixture that Victoria prepared had a lightening effect. That’s why her lengths were a brassy red. And her roots, which always absorb dye faster, were carrot orange.


Luckily, I was able to fix Victoria’s color.

Of course, it wasn’t immediate. I had to apply several products to correct the color and, finally, get to the 4.1 ash brown.

If you don’t want the same thing to happen to you when mixing different volume developers, read on.

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Why shouldn’t you mix a 10 and a 20 volume developer?

dye your hair twice in a short time

First of all, why do you want to make that mixture?

 Don’t you find it easier to buy the 30 volume developer directly?  


Now, if what you’re looking for is to use 30-volume developer, I must tell you two things:

  • The 30-vol will fade or lighten your color up to three levels.
  • In some cases, it’s used to dye gray hair, which is harder to process.


If you’re looking for any of those objectives, I recommend you go to a professional.

  • Otherwise,  you’ll  get an uneven and bright color.
  •  Alternatively, if you want to dye your gray hair , you’re looking at a complex job. You’ll have to mix 30 vol with a dye and apply it on the gray hair. Then, mix 20 vol with the same dye to cover the lengths.


Mixing different developers isn’t the best option.

  •  If you want to lighten your hair naturally, you should simply use a 10 volume developer.  If you use higher volumes, you’ll lighten all your hair up to three levels.
  •  Alternatively, if you don’t have enough 20-volume developer, and you add 10-vol , your roots will be lighter than the rest of your hair.


So, I repeat.


You shouldn’t mix developers of different volumes if you’re not a professional colorist

keratin in dyed blonde hair

A developer is a chemical product that opens the cuticles of your hair, which are small scales that cover your hair and protect it.

When you apply a developer, the cuticles open, and the core is exposed. Therefore, it expels the color when it’s bleached or absorbs the color during a coloring job.


 Each developer has a specific oxidizing strength. 


The greater the volume, the greater the reaction. Therefore, the more damage to the hair.

  • The 10 volume developer doesn’t open the cuticles completely. It’s used to brighten the hair in a very subtle and natural way.
  • The 20-volume developer opens the cuticles completely, and is used to apply permanent hair dye.
  • The 30 volume developer opens the cuticles completely, lightens the hair up to three levels, and is used in bleachings to achieve high-lift blonde.


So, you should use the right volumes of developers according to what you want to achieve.

  There’s a right amount of developer volumes for every hair coloring goal. 


Don’t mix developers of different volumes to avoid ruining your hair in a way that it’ll need months to recover moisture and nutrients.



Don’t mix different volume developers unless you are a professional colorist.

If you mix a 10 volume developer with a 20 volume developer, you’ll get a 30 volume developer that will dry out your hair and lighten it up to three levels while producing an uneven and unwanted bright color.

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