Does Protein Treatment Straighten Hair? Not exactly, here’s why

woman with hair straightening product

  • Protein treatment doesn’t permanently straighten hair because it’s a nourishing treatment. The only treatment that has that effect on hair is permanent straightening because it modifies its structure.
  • If your hair is straight, wavy, or with loose curls, the keratin treatment will eliminate its frizz. That’s why your hair will look straighter. However, this straightening effect lasts two weeks maximum, depending on the washing frequency.
  • If your hair is afro, you can apply a protein treatment because your curls won’t disappear. Those protein treatments are applied without heat.



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Do you struggle with split ends despite trimming them every two to three months?

Does your hair feel dry and brittle?

Have your curls lost their joy and body?

Then, your hair needs a protein treatment. Why?


Although our hair naturally contains protein, exposure to environmental conditions and product buildup generates a gradual loss.

This is where protein treatment comes in because it nourishes and strengthens the hair.

Now, in addition to taking into account the needs of your hair, do you have other expectations?


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 For example, if you want a protein treatment to straighten your hair, you won’t achieve it. 

In that case, you’ll have to apply a permanent straightening treatment to change the molecular structure of the hair permanently, as the name suggests.

I’ll explain this by telling you the story of two of my clients: Agustina and Jeni.


Agustina is an adorable 17-year-old teenager. She’s pure energy and has wavy hair. However, she takes very little care of her hair.

She flattens it more than three times a week, and I don’t think she’s ever heard of deep-moisturizing hair masks.


Jeni, on the other hand, is a 20-year-old girl. She was born in a small fishing village in the south of Brazil. Besides the fact that I love her name, which means “born of the moon,” I admire the dedication she puts into her afro hair.

Her hair requires a constant balance of moisture and protein to keep the curls looking their best.


In Agustina’s case, I decided to apply one of the most popular protein treatments that is keratin.

What she wanted was to nourish her hair and eliminate frizz. Also, since Agustina’s hair isn’t very wavy, she wanted to straighten it.

In this case, the protein treatment was applied by sealing the keratin with heat.


In Jeni’s case, things were completely different.

She loves her afro hair. She wouldn’t give up her curls for anything in the world. But her hair needed deeper nourishment than a hair mask can provide.

Therefore, I applied a protein treatment without heat. If she had applied a protein treatment like keratin, even for a few weeks, her curls would have been looser. And she can’t go a day without her curls.

Can you see the difference?


 Nowadays, there are plenty of protein treatments that fit your hair’s needs and expectations. 

If your hair is very curly, and you don’t want to lose its shape, you can opt for a protein treatment that is applied without heat to avoid modifying the curl pattern.

So, to avoid any doubts, I’ll be categorical.

Tabla de Contenidos


Protein treatment may temporarily straighten hair

keratin treatment on colored hair

You already know that the main purpose of keratin treatment is to nourish and repair the hair.

So, unless you have afro hair, your hair will be frizz-free after applying the protein treatment. Also, the straightened look will last for two weeks.


 So, if your hair is straight, wavy, or with very loose curls, it’ll be temporarily straightened after the protein treatment. 



Because many protein treatments are applied with heat to seal the nutrients inside the hair. As high heat is needed, both a blow dryer and a flat iron are used.

So, what can you expect from protein treatment?


  • Frizz-free hair
  • Shine
  • Docility
  • Softness
  • Resistant hair
  • Less hair breakage when brushing it


As you can see as you read this, there is no such thing as straightening among the benefits of a protein treatment.

If your hair is afro or very curly, a protein treatment won’t straighten it.

You need another type of treatment to change the curl structure permanently, such as extra strong straightening.


If you’re looking for a protein treatment that doesn’t change the appearance of your afro hair, the stylist will offer you one that doesn’t include ironing the hair. In this case, standing dryers are used to allow the nutrients to adhere to the hair.

Therefore, we come to the second conclusion.


Protein treatment and hair straightening are two different things

  • Protein treatment repairs and nourishes the hair.
  • Straightening, meanwhile, changes the internal structure to achieve the straight effect

You need to keep this difference in mind if you don’t want to be disappointed with the results.


 The protein treatment will leave your hair soft, shiny, manageable, AND frizz-free.  Your hair will feel stronger and heavier, with more elasticity, and “straight” for at least two weeks.

Straightening will leave your hair volatile, frizz-free, shiny, and soft. However, it will be lighter, tangle easily, and the greasiness will be much more noticeable.



The protein treatment nourishes the hair because it absorbs the proteins. Straightening, on the other hand, is an aesthetic treatment that “laminates” the hair on the outside by closing and sealing the cuticles.

To put it more simply: protein treatment acts on the inside of the hair while straightening acts on the outside.



If you want a nourishing treatment with a temporarily straightening look, you can opt for a protein treatment.

However, if you want to maintain the curl pattern of your afro hair, you can opt for a protein treatment without flat ironing.

Finally, if you want to straighten your hair permanently, you should apply a straightener.

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