Side Effects of Keratin Treatment; Everything You Must Know

If you want to try a hair smoothing therapy like the Keratin Treatment or Brazilian Blowout on your hair to have them straight everywhere you go but are worried about the aftermath of such a styling procedure, we got you covered with the details.

Featured Image of Side Effects of Keratin Treatment

It is definitely true that such hair treatment comes with serious side effects that can affect your hair and health.

Alongside its wonderful sleek, straight results, this semi-permanent hair treatment also has some serious drawbacks, which are not discussed often. 

The 3 Most Hazardous Side Effects

1. Keratin Treatment Can Cause Cancer

Many of the keratin treatments used for hair smoothing purposes incorporate a chemical named Formaldehyde.

Formaldehyde is a colorless, strong-smelling gas that helps eliminate annoying frizz from your hair while keeping them smooth and straight for months.

Nevertheless, the U.S. Environmental Protection Agency declared this component dangerous.

Namely, this chemical can cause cancer (or help cancer grow or spread) if exposed to it for a long time.

Are you wondering how this chemical gets inside your body?

When you get your hair straightened and smooth, Formaldehyde gas is released into the air from the treatment solution, which then gets into your system while you breathe in the fumes and your skin absorbs it from the air.

Aside from you (who is getting the keratin treatment), the hairdresser helping you is also at great risk of suffering from cancer and other health hazards.


2. Has the Risk of Causing Severe Allergic Reaction and Other Health Problems

In addition to being a carcinogen (a substance that might cause cancer), formaldehyde is also known to trigger other health side effects and severe allergic reactions to cause extreme discomfort.

From itchy skin to coughing, sneezing, and mood swings, this chemical can turn your world upside down.

Hence, in 2016, the Environmental Working Group and Women’s Voices for the Earth (EWG) sued the Food and Drug Administration (FDA) for not regulating formaldehyde use in beauty and hair care products(1).

EWG claimed that the FDA was well aware of the health hazards associated with the products containing formaldehyde for at least 10 years, but they failed to regulate it.

Many users and salon stylists have faced difficulty breathing, eye irritation, and nosebleeds after using this straightening treatment.

Some of the most noticeable allergic reactions from formaldehyde you should know about are:

  • Runny nose
  • Itchy, burning eyes
  • Coughing, wheezing, sneezing
  • Chest tightness
  • Itchy skin, skin rash
  • Scalp irritations and burns
  • Headaches and nausea
  • Mood Swing
  • Nose and throat irritation

3. Potential Increase in Hair Breakage and Damage

Damaged Hair - V1 Sep

One of the main steps during keratin treatment is drying your hair using heat and straightening them with the best keratin hair straightener or flat iron for an outstanding result.

However, if you apply too much heat for quick drying or over-straighten them with high heat to lock in the treatment deep into each hair strands, your hair is more likely to suffer from extreme breakage in the long run.

Additionally, when the heat is applied to the hair, it releases more formaldehyde into the air, t exposing the people around you to health problems.

Additionally, since the formaldehyde causes scalp irritation, your scalp becomes sensitive, which weakens the hair root leading to extreme hair loss.

Related: How Often Can You Redo a Keratin Treatment?

How to Avoid the Damaging and Dangerous Side Effects of Keratin Treatment

In our opinion, you should never try any permanent or semi-permanent treatment on your precious hair.

Nevertheless, once in a while, you might want to switch up your hairstyle.

If you want to try a Brazilian Blowout, we recommend choosing a hair salon that doesn’t use formaldehyde infused treatment chemicals.

Instead, you can ask your stylist to use glyoxylic acid on your hair, which is much safer but ensures the same smoothing and straightening results as formaldehyde.

Another salon treatment you can try instead of the Brazilian Keratin is the Keratin Complex.

This procedure uses different formulas from a classic smoothing treatment to repair your damaged hair and make them silky, smooth, and frizz-free.

But, this treatment doesn’t straighten your hair, and therefore, you are not exposed to any dangerous effects caused by formaldehyde.

On the other hand, if you wish to practice this salon treatment in your home’s comfort, we suggest this INVERTO REVOLUTION Complex Brazilian Keratin Formaldehyde Free Hair Blowout Treatment, which has no Formaldehyde present in the formula.

Hence, now that you have an obvious idea about keratin treatments’ dangerous side effects, we hope you make a smart decision before trying it on your hair.

READ MORE: Keratin Treatment Pros and Cons




  1. Hello!

    I am a regular reader of your blogs. Some of your writings are just wow. They are really praising worthy.

    But why did you write this article? Don’t you think this piece of writing would discourage others to go for keratin treatments?

    Looking forward to your response!

    • Dear Lee Naa

      Thank you for reading our blog regularly. We are pleased to know that you liked them.

      This article was written to inform our readers that even though keratin treatment gives your hair a lustrous look, there are some severe side effects that you must know about and be prepared for that.

      It was not meant to encourage or discourage anyone.

      Stay with us!

    • I’m grateful for this article. I’ve started using the Keratin hair growth formula and developed a rash on my neck and scalp. I stopped taking it for a week and the rashes and itching subsided but as soon as I took another dose the rashes returned so now I’m sure it’s the KERATIN .. there was no warning of this possible side effect.

  2. Cancer!?

    Are you sure that keratin hair treatment causes deadly cancer?

    I haven’t heard anyone getting this disease after a keratin treatment?

    Please check your facts first.

    • Dear Teri,

      If you are a regular follower of our blog, you would know that we never put something up when we are not 100 % sure.

      We have checked our facts and then stated this in our article.

      We hope we could provide you the answer.

  3. You people never fail to amaze me.

    This is one of the best informative articles I have read in a long time. You guys managed to keep it clean, minimal yet full of useful information. That’s the true beauty of writing.

    Hats off to the writer as well as the researchers!

    Keep on writing like this.

    • Dear Angelina,

      Thank you very much for your praise words. Our readers’ feedback is what keeps us motivated.

      Stay with us!

  4. I agree with your article. It’s to the point and brought up everything thing a person might suffer from after getting a keratin hair treatment.

    I did get this procedure done once in my hair. And you won’t believe what I had gone through right after. From runny nose to sneezing and red eyes, I suffered from everything.

    At that time I thought it was cold. But now I understand what it was.

    Thank you for such an amazing article.

    Lots of good wishes!

    • Dear Edward,

      We are extremely sorry to hear about your experience. That was really awful.

      And thank you for sharing it with us. Our readers might find it helpful.

  5. Excellent idea and amazingly penned article!

    I really enjoyed reading it from top to bottom.

    Readers will get a very clear and informative idea about the deadly effects of keratin treatment from this article.

    Keep up the good work!

    • Dear Dian,

      Thank you so much for your sweet words. We are inspired and motivated by such empowering words.

      Stay with us for more of such articles.

  6. I have been following your blog for the longest time.

    Can you tell me after exactly how many treatments I will get cancer?

    I am really worried because I have done keratin treatment quite a few times to date.

    Please respond ASAP.

    • Dear Missa,

      Thank you for following our blog regularly.

      Unfortunately, there is no exact number of treatments that would determine what you have asked for. It depends on your immune and health conditions.


Leave a Comment