Does keratin change your hair color? Can it darken it or lighten it?

Smoothing changes the color of dyed hair

A keratin treatment can lighten your dye one or two tones, if the color you have is between light brown and blonde. In black and red colors, the change is almost unnoticeable.

Meaning, that the straightening treatment will darken the color of the dye, and if it lightens it, it will depend on the tone of your hair.

Now, if you don’t want your color to change, it’s important that you respect the order that you apply the two process to your hair.


If your color is natural, meaning, you’ve never applied any dye to your hair, the color won’t change. Dark brown will continue being dark brown; blonde will continue being blonde.  

If you use the keratin correctly, the color of your hair will not change and you will get the best out of this treatment, which is a true wonder for your hair.


While telling you this, I remember Elena’s case.

Elena is one of my clients, one of those clients that was always, always very proud of their hair.

And the truth is that she had her reasons. Her hair was long with light waves which looked more like a waterfall than a mane.


 The problem is that Elena was tired of using the flat iron to straighten her hair. Every day on average, she had to wash her hair, dry it with a hair dryer and plan an hour to use the flat iron.  

It was exhausting, not just because flat ironing such long hair can be quite a feat, but also because she slept less time than she needed. And this was causing her problems in her daily life.


It was hard for her to concentrate on her studies, she forgot about important things in her work, and she felt more tired.

That’s why, a month ago, she came in to do a keratin treatment. After evaluating her hair, it seemed to me like a good option.

First, because her hair was dry and damaged from using heat tools. And second, because she wouldn’t have to get up two hours earlier to straighten her hair.


Her hair ended up precious. You could tell that the keratin had done its job. Don’t forget that it’s a protein, which has the ability to fill the hair fibers, giving it back nourishment and moisture.

The constant use of the flat iron and hair dryer strip out the proteins that are naturally found in the hair. That’s why your hair ends up unstable and weak, and frizz appears.

Can you imagine how your hair would look under a microscope?


To give you an idea, your hair can look like a path with cracks and ruts or a piece of limestone with small holes.

So, Elena left my salon enthusiastic, happy, and delighted that day.

But that happiness lasted about five days.


 Because when she came back to the salon after five days, her hair was… I don’t know how to explain it … an opaque, dull brown, but the worst part was that there were stains all over. 

When I asked what had happened, she told me that she had applied dye, the same dye that she had used every time that she dyed her hair. She had used the same brand and had let it sit for the same time.


My eyes jumped out of my sockets. Yes, just like in the cartoons. I couldn’t believe it!

How could she have even thought about applying hair dye four days after applying keratin!


I don’t want to be tough, but I sometimes think that when stylists do these types of treatments, there is some sort of transformation that goes beyond hair. It’s as if the neurons were replaced by little birds.

Do you want to know what had happened to Elena’s hair and why the keratin had changed the color of the dye?


Then don’t move, because I will tell you:

  • Why keratin can modify the color of your dye and how to prevent it
  • How the keratin works with the natural color of the hair


Now you will have no excuses for ruining the color of your hair with keratin.


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How to prevent keratin from lightening the color of your dyed hair

I still haven’t gotten over seeing Elena’s face of desperation and fear.

My goodness! Why didn’t she simply send me a WhatsApp to ask me if she could dye her hair?


She would have avoided the terror that her hair ended up.

And most importantly, she wouldn’t have thrown away more than one hundred fifty dollars that she spent on the treatment and after on the dye.


This is very simple.

So that the keratin doesn’t interfere, nor lighten the dye, you should apply the color at least fifteen days after straightening your hair.


The explanation is very simple.

The keratin forms a light layer over the hair and the chemical products present in the dye don’t penetrate the this layer properly.

That’s why your hair can end up a different color and even looked stained.

 So, it’s important that you color your hair fifteen days after the keratin


Now, if you already have hair dyed blonde, for example, and you do a straightening treatment, most likely you will have some pieces of hair that end up a yellow color. But don’t worry, because this yellow will fade with the first wash.

Brunettes and red heads, have it best because the keratin won’t modify the color of their dye.


There is also another possibility when it comes to keratin and coloring.

Has it ever happened to you that keratin can enhance the color as well as nourish your hair after dyeing it?


To do this, you simply have to dye your hair ten days before doing the straightening treatment. This way, keratin will seal in the pigments of the dye at the same time that it restores the natural moisture of your hair.

Now, what happens with the keratin in hair that isn’t dyed?


In natural hair, keratin doesn’t lighten it or darken it. Because there are no chemical pigments which can interfere.


Conclusions about coloring and keratin

As you can see, keratin and hair dye are two roads that on many occasions cross.

In Elena’s case, we waited about fifteen days and applied the color again. Since she didn’t want to run any risks, she did it at the salon.

And then, she got the same smile back from when she straightened her hair.


That’s why if you dye your hair and you apply keratin, always keep in mind that:

  • If your hair is dyed among the gama of light browns and blondes, the color can lighten one or two tones.
  • If your hair is dyed black or red, the dye won’t lighten.
  • If you still haven’t dyed your hair, you have two options: apply the color ten days before straightening it or dye it fifteen days after applying the keratin.


Lastly, keratin never lightens or darkens the natural color of your hair.


Do you have any other doubts about coloring or keratin?

Write me, and I will answer all your questions.


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