How long can hair dye last after mixed?


wet hair

  • How long does dye last after mixing it? Once you’ve mixed the dye, it lasts 30 minutes. That means from the time that you finish preparing the dye and peroxide mix until you finish applying it to your hair, you have 30 minutes.
  • Let’s say you finish preparing the mix at 10 am, then you’ll have until 10:30 am to use it on your hair.
  • Once the half an hour has gone by, the mix won’t do anything and it won’t have any effect on your hair. If you have any mix left, you should toss it.

Why does the mix only last half an hour?



The mixture you use to dye your hair contains dye and peroxide (developer).

The peroxide chemically reacts when it comes into contact with oxygen.

 This reaction is good for a maximum of 30 minutes. It doesn’t matter if you’ve applied the mix to your hair or not, the mix lasts the same amount of time.  



Half an hour might be more than enough or very little time, depending on how much experience you have with dyeing your hair.

If you don’t have a lot of experience, half an hour might seem like not enough time. If that’s the case, then I’d recommend you ask something you trust for help. Maybe your sister, your cousin, etc.


The most important thing is that someone helps you to make sure that the half an hour is enough.

If you have experience, then half an hour should be more than enough.

Now, which should you do first, section your hair or prepare the color mix?



It’s better to section your hair first and then you can prepare the mix. Why?

 Because if you first prepare the mix and then you section your hair, the mix will already be reacting and you won’t have enough time to apply it to your hair.  


Sectioning your hair can take some time. And it can take even more if you’re doing cap highlights, for example.

How long do you think it takes to pull the strands of hair through the cap’s holes?



It takes a good long while.

That’s why you should always prepare your hair first, whether you need to section it or prepare it for highlights, and then once your hair is ready, you can start to prepare the mixture. That way, you’ll be sure that you have enough time to apply the mix to your hair.


My cousin decided to dye her hair for the first time a few months ago.

Since it was the first time dyeing her hair, most sensible people would decide to go to a professional salon, right?



But cousin isn’t always the most sensible.

So, she bought a color kit in the supermarket and dyed her hair at home. The result?


A hair disaster!

And all because she prepared the dye mix first, then she sectioned her hair.

 By the time she started applying the dye mix to her hair, 25 minutes must have already gone by. And so, of course, she applied all this mix that wouldn’t have any effect on her hair.  

Her time spent applying the mixture to all of her hair after the half an hour went by was completely in vain.



To avoid the same thing happening to you as happened to my cousin, I want to give you a few pieces of advice that will help you take full advantage of the half an hour you have until the dye stops working.


4 secrets to best take advantage of the half an hour you have to apply the dye

apply the mixture before half an hour

The first and most important trick is the one that we already talked about.



  • You should section your hair and then apply the mix. Don’t do it the other way around because you won’t have much time to apply the mix to your hair.


  • Another interesting idea is to divide the dyeing process into two parts.

You can prepare half of the mix and apply it to your hair.

Then, you’d prepare the other half of the mixture and apply it to your hair. This idea works well for covering grey hair, for example.


The process would go something like this.


First, you’d prepare half of the mix and apply it to your roots, grey hair or roots with grey hairs.

You let it sit while you prepare the second half of the mixture. When 20 minutes have gone by, then you apply the second mixture to the middle and ends.


  • Many kits come with a tool to apply the mixture. I don’t recommend using it. It’s much quicker to apply the mixture with a hair dye brush or with your hands (with gloves on).


  • You should prepare the mixture in a plastic container. Both metal and glass inhibit peroxide’s effect.

That means that if you prepare the mixture in a metal or glass container, the peroxide won’t undergoe the necessary chemical reaction.




So now you know how long the dye mix lasts.

Before using any dye, it’s a good idea to closely read the usage instructions. And that applies to kit dyes as well as dyes that come in a tube.


 I know that reading instructions isn’t exactly the sexiest thing in the world, but believe me that you’ll save yourself more than one headache in the future if you do. 

My dear cousin can definitely attest to that.


Remember that each brand and even each line of dye, might have their own unique specifications. That’s why it’s so important to read the instructions that they come with.


Now you know how long the prepared mix lasts.

And you also know that you can’t keep the mix after 30 minutes, because once that time goes by, it won’t even work on your favorite doll’s hair.

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