Is it true that hair dye works better on dirty hair?

with shampoo

  • Hair dye does NOT work better when you use it on dirty hair. You can wash your hair the same day you dye your hair because it won’t affect the outcome of the dye. I’ll tell you about where this myth comes from.
  • Now, if you have a sensitive scalp, that changes things a little. If that’s the case, it’s a good idea to wash your hair 48 hours before dyeing it. For example, if you have an appointment at the salon to get your hair dyed on Thursday, wash your hair for the last time before your appointment on Tuesday.


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The number of myths floating around about hair care is incredible.

One such myth is that if you pluck a white hair, three more will grow in its place. Another is that your hair “gets used to” shampoo. And of course, that legendary one.

Say it with me:


You should dye your hair when it’s dirty.

 I can’t even describe how annoying it is when I have to work with someone in the salon that hasn’t washed their hair for 10 days because they think that the dye will work better on their hair that way. 

How can someone even go ten days without washing their hair?


Yes, I said that right: Ten days!

I can’t even imagine how they’re able to make it through five days with dirty hair. Nobody in their right mind would want to go more than three days without washing their hair.

If you don’t wash your hair for three days, all you’re going to do is get a bunch of flies to follow you around, swarming your head and announcing to the world your lack of hygiene.


You’ll also make your scalp start to emit a certain fragrance, but of course, it won’t be the same kind of fragrance as your favorite perfumes…

Come on, ladies! It’s the 21st century! Wash your ears out, too, so you can hear clearly what I’m about to say:

 Your hair does not have to be dirty to dye it because today’s hair dyeing products are 100% safe!  

Even if they do contain ammonia, the doses they have are the exact right amount necessary to ensure that they won’t hurt your scalp or your hair.


A long time ago – and I mean that, like many, many years ago – dyes were aggressive for your hair because they used a lot of ammonia to help make the dye’s pigments stick.

But, things have changed. A lot. So please let’s just move on from dirty hair.

Of course, there are a few exceptions.

Do you want to know what they are?


I’ll tell you in a moment and I’ll also tell you:

  • How long before you dye your hair should you wash it
  • When you shouldn’t wash your hair before using hair dye


Are you ready to do some myth-busting? Let’s get to it!

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How long before you dye your hair should you wash it?


Back in the olden days, dyes were aggressive both for your hair and for your scalp. And many people indeed experienced allergy-like symptoms and irritation on their scalps, because of the ammonia.

But, thanks to the technology that the big hair care brands use, like L´Oreal and Koleston, there are new dyes that are less aggressive because they use a smaller amount of ammonia.


  •  That’s why way back then hair colorists recommended not washing your hair for 3-4 days before dyeing it.  What they were trying to do was help their clients avoid a burning or itching sensation on their scalps and even peeling.

But, those days are behind us.


  • Today, the amount of ammonia that dyes use isn’t aggressive, which is why it does not usually provoke any kind of allergic reaction and they are better are depositing color than ever before, which is why they are so safe to use.

So, the question is: Should I wash my hair before I dye it?


  • No. Washing it right before you dye it doesn’t really make sense. It wouldn’t be either better or worse in terms of the dye depositing pigments into your hair.[ /su_list]

What I’d recommend doing is keeping it clean, following your normal pattern of washing your hair. That way, you can have clean and bright hair before dyeing it and not gross everyone around your out.

What happens if two days go by, you don’t wash your hair and then you use the dye?


  • The dye will work just the same. If it doesn’t bother you not to wash your hair for two days, then go ahead and do it.

But what I wouldn’t recommend is letting more than three days go by without washing your hair.

Because in that case, some residue from environmental pollution as well as from any hair products you use, can accumulate, which will make coloring your hair harder.


Now, in the beginning, I told you that there are a few exceptions, just like there are to every rule.

And that is because not every one’s hair and scalp are the same.

Do you want to know when it’s not a good idea to have completely clean hair before dyeing it?


Keep reading.

There are two cases where you should avoid washing your hair before dyeing it: if you have a sensitive scalp or if you have greasy hair. Let’s look at the specifics of each situation.


If you have a sensitive scalp, don’t wash your hair for at least 48 hours before dyeing it

If you have a sensitive scalp, then ammonia might not be your best friend. These days, some dyes don’t contain ammonia, so you can opt for one of them if your scalp gets irritated easily.


 However, if you prefer dyes that do contain ammonia, you can use them, but in this case, I recommend not washing your hair for at least two days beforehand, and three would be even better if you can manage it. 


Your scalp’s natural oils, from sweat and sebum, will form a hydrolipidic film on your head that will protect your scalp.

So, if you have a sensitive scalp, that protection will help prevent any kind of allergic reaction like peeling, pain, or redness.


If you have greasy hair, wash your hair 24 hours before dyeing it

How do you know if you have greasy hair?


Well, for example, if you wash it in the morning and it’s opaque and flat by the night, you have greasy hair.

Will dye work on greasy hair?


Of course, it will,  but it’s a good idea to wash it a few hours before you dye your hair as a precaution, at a maximum 24 hours before you’re going to dye it. 

Do you want to know an advantage to dyeing greasy hair?


The ammonia will act as a super-charged cleaner on your scalp and it will leave your hair extra clean and bright.

Then, when you rinse the dye, be sure to get all of the product out before using your shampoo so your hair doesn’t end up weighed down by product you didn’t get out.



Your hair does not have to be dirty to dye it. Wash your hair as you normally would, and you can use dye on your hair without running into any kind of trouble.

Now, if you have a sensitive scalp, then it’s a good idea to wash your hair 48 hours or more before you dye it.

And if you have greasy hair, 24 hours will be enough.

So, now you know, being dirty isn’t a good thing, even when it comes to dyeing your hair.

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