How long should you leave Keratin in your hair? Is it dangerous to leave it in for longer?

selfie in front of the mirror

After years of doing keratin to dominate the frizz in my hair and to get my hair to look tidier, I can assure you that keratin should be left in for between 15 and 30 minutes. The amount of time will greatly depend on the brand of keratin that you use.


Now, many people have this doubt.

 Is it dangerous to leave keratin in your hair for longer than necessary?  


To respond to this question, I will tell you my experience from a few months ago.

Do you remember “Money Heist,” the Netflix series that everyone was talking about?


I got sucked in from the beginning.

That professor that came up with such a masterful plan and that at any moment it seemed like everything was going to go to hell. It had me hooked.

It was the final episode.


Unfortunately, I had done a keratin treatment and I said, “After thirty minutes, I’ll stop and it’ll be ready.”

But when you’re trapped in a plot…

When you feel like if you blink you’re going to miss something important…

Time doesn’t count.


So, when I jumped from my seat with the spectacular final of the series, that I won’t tell you in case you haven’t seen it, I touched my hair and remembered that I had done the keratin.

I’m not going to lie.


While I ran to the bathroom to rinse my hair, I thought that my hair would fall out.

My scalp would have holes in it.

And when I used the flat iron, the hair would literally melt away.

But none of that happened.


 If you leave keratin in for ten, fifteen or twenty minutes more in your hair, nothing bad will happen. 

But don’t abuse it.

There is a reason for labels on products.

I think that also, the time has to do with the maximum performance of the product each time that you apply it.

At least, with dyes that’s what happens.


There gets to a point where no matter how long you leave the dye it for longer than you need, the hair can’t absorb more and the only thing you achieve is damaging your hair.


My advice is don’t risk it.

The longer you leave the keratin in your hair, the results will be the same.


At any rate, from that experience, I decided to not watch more series when I do the keratin.


If you want to know everything about the application times of the keratin in your hair, stick with me because I will tell you:

  • What things are important while you apply keratin in your hair
  • Two brands of keratin that have given me excellent results and how long you should leave each one in your hair


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Everything about the times of application of keratin: What should you keep in mind when you apply the treatment?

leave it at least half an hour in hair

Are you ready to do a keratin treatment at home?

Then the first thing is to assure that you are doing it well.



First off, for three reasons:

  • If you are going to do a keratin treatment, it’s because you want to get a change in your hair, either to make it straighter, to eliminate frizz or to nourish it.
  • You are going to invest time and time is gold.
  • You invested money, and what I know is that unless you are a millionaire, each coin counts to get to the end of the month.

That’s why it’s important to respect the application times of the keratin to get the desired results.

Let’s get started.


How to apply keratin for the correct time

Wash your hair, if you have very curly hair, I recommend that you wash it two times.

And please, don’t even think about using conditioner.


Dry your hair with a towel.

I know a lot of people recommend applying heat with the hair dryer, but I do it with a towel and I wait for my hair to dry naturally until it is about 80% dry.


After, apply the keratin piece by piece, leaving at least two centimeters from your scalp.

Let the keratin sit for thirty minutes on your hair, and when the time has passed, brush you hair softly to get the extra out.


The rest, I think you know already.

Dry your hair with a hair dryer and arm yourself with patience to use the flat iron, piece by piece at least fifteen times on each chunk.

Look at yourself in the mirror.


You’ve done it.


How long to leave each keratin brand in your hair

Each brand of keratin has different needs.


That’s why my advice is that before anything, read the instructions that come with the product you have chosen.

And I generally use two products.

The classic Kativa straightening and sometimes the Alfaparf keratin kit.

After using them for various years, I know how long to leave each one of the products in my hair for.

And right now, I’m going to tell you.


Kativa Straightening

leave for 15 minutes in hair


I recommend kativa straightening for more impatient people, because you only have to let it sit for fifteen minutes. At least, that’s what the label says.

Now, my personal advice is that if you have really curly hair and you want it straight, leave it in for thirty minutes.

You hair won’t be put through any danger.


Also, if you have bleached hair, it won’t interfere with the tone of your hair, meaning that it won’t get lighter or darker.

I just have one critique about the product and it’s that it smells a bit weird the first few days, but after that, your hair will look frizz-less and shiny.


Alfaparf Keratin Therapy Lisse Design

one use only


This is an excellent product, more than excellent in reality.

Any product from the Alfaparf Laboratories has never failed me.


You might be asking yourself, then, why I put it as the second position in my recommendations.

And the answer is because this product is for patient people.

Very patient.


Because it’s actually a four-step kit.

The keratin itself you only apply for twenty minutes, but there are some other steps with different products, like shampoo and a mask that you should use to complete the treatment.

The kit comes with all the instructions, which is why I’m not going to explain them here, because I don’t want to be annoying.


But the results are incredible.

You’ll see that you almost never have to use the flat iron to get straight hair without the frizz.



Before going ahead with the keratin, read the instructions that come with the treatment kit that you’ve chosen very well.

In general, at-home keratin kits like the ones named above, require the product to be left in your hair for maximum thirty minutes.

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