Keratin Treatment Vs. Relaxer: The Difference Explained

Take the right decision for your precious mane as you understand these two procedures.

Medically Reviewed by Dr. Rinky Kapoor, MBBS, DDV, MD
By Ramona Sinha, Certified Skin Care Coach

As much as you love your exquisite curly or coily textured tresses, there may be a point when you want to get your natural hair straightened. But once you head to the salon, you are confused between a keratin treatment and relaxers. If you are pondering over the difference between these two processes, scroll on.

Both processes transform naturally textured hair and make it smooth, frizz-free, and straight. Whether you want to change your hairstyle or spend less time managing your locks, you can consider either of these treatments. Here, we explain the inherent differences between both these processes so that you can choose the best one for your hair. Keep reading to know more.

What Is Keratin Treatment?

Keratin treatment is often known as Brazilian keratin treatment or Brazilian treatment. It is a semi-permanent process that focuses on hair strengthening without disrupting its texture.

Keratin is a protein essential for your hair’s structural strength. Keratin-rich products contain L-cysteine or cysteine, a non-essential amino acid that supports hair health and slows down hair loss and breakage (1).

Woman showing before and after effects of a keratin treatment


This professional hair straightening treatment infuses the hair strands with keratin to de-frizz the hair and make it smooth, shiny, and strong. It works on all hair types. However, if you have damaged hair, consult a professional hair expert before undergoing the treatment.

In the following sections, find out how the process works and what to expect.

How Does It Work?

How A Hair Strand Improves With the Keratin Treatment


Keratin hair treatment products contain hydrolyzed keratin proteins mixed in a formaldehyde-releasing solution. During the treatment, the hydrolyzed keratin adheres to the hair cuticles. As a result, the sub-cuticle section of the hair strands relaxes, giving you flat, smooth, glossy, and shiny hair.

Different Types Of Keratin Treatments

Woman Getting A Keratin Treatment Done In A Salon


Some of the common types of keratin treatments include:


Keratin hair treatment is usually done in a salon. It involves the following steps:

  1. The hair expert will shampoo your hair and blow-dry it (80% dry).
  2. The semi-dry hair is saturated with the keratin protein solution.
  3. The solution is left undisturbed for 30 minutes.
  4. The saturated hair is blow dried, followed by flat ironing to ensure proper absorption of the solution.
  5. You may be asked to leave the hair as it is for about a day or two.
  6. After the stipulated time, the solution is washed out of the hair, followed by blow drying.

Time Required

Keratin treatment requires 3 to 4 hours, depending on your hair length, volume, and condition.


  • Do not wash, style, or tie your hair for at least 72 hours after the treatment.
  • Use sulfate-free hair products to wash and condition your keratin-treated hair.
  • Avoid excess UV and chlorinated or salt water exposure to prevent any damage.
  • Switch to keratin, zinc, and biotin-rich hair products for maintaining keratin-treated hair.

Note: Consult a hairstylist for product recommendations.

How Long Does It Last?

Keratin is a semi-permanent treatment and may last on natural hair for 3-6 months, depending on your hair care habits.

Risks And Side Effects

Keratin-based hair products contain formaldehyde in large concentrations. The FDA recognizes formaldehyde as a human carcinogen, as prolonged exposure to this chemical may cause certain types of cancers (2). The procedure often releases a strong-smelling gas that may trigger (3):

  • Respiratory distress
  • Itchy and watery eyes
  • Sore throat
  • Burning sensation in the eyes
  • Coughing and wheezing
  • Nausea
  • Skin irritation


Professional keratin treatments cost anywhere between USD 200 to USD 800.

Now that you know all about keratin hair treatment, let€™s check out everything about hair relaxers or chemical relaxers.

What Are Hair Relaxers?

Woman Showing the difference between relaxed and curly hair


Hair relaxers are chemical-based products specifically formulated to relax and smoothen curly or kinky hair. Some formulations can also condition and moisturize the hair, reduce frizz, and improve hair texture. However, hair relaxers will not make your hair poker straight.

In the following sections, find out more details about how hair relaxers work.

How Does It Work?

Hair or chemical relaxers disrupt the disulfide bonds between the protein structures in the shafts of the hair (4). This alters the hair’s natural structure and texture.

Different Types Of Hair Relaxers

Hair Relaxing Results: Before and After


You can opt for different types of hair relaxers like:

  • Lye relaxers or sodium hydroxide relaxers (suitable for wavy, coily, and curly hair)
  • No-lye relaxers or calcium hydroxide relaxers (suit all hair types)
  • Ammonium thioglycolate relaxers (suit fine, wavy, and curly hair)

The difference lies in the strength of the chemicals used in these relaxers. Always consult a hair expert to understand which may suit your hair type.


Unlike keratin treatment, hair relaxers can be used at home. Here is how to use them:

  1. Coat your hair with petroleum jelly to prevent scalp and hair damage.
  2. Apply the relaxer (cream or lotion) to the hair ends and work your way up the strands.
  3. Leave the relaxer on for 15 minutes and rinse it out with warm water.
  4. Wash your hair with a neutralizing shampoo and condition it to balance the pH levels of the scalp.
  5. Apply a hair moisturizer.

For touch-ups, follow the same process. However, do not apply the product to the hair ends.

Time Required

The hair relaxing process takes about 30-60 minutes.


  • Use a gentle, sulfate-free, reconstructing shampoo.
  • Avoid frequent shampooing.
  • Apply leave-in conditioners or deep conditioners to maintain moisture balance.
  • Use hydrating and protein masks.
  • Avoid heat styling.
  • Trim the dry and brittle hair ends.
  • Never relax color-treated hair.

How Long Does It Last?

Hair relaxers are semi-permanent, and the effect may wear out after 6-8 weeks.

Risks And Side Effects

Hair relaxers have a pH between 9-12 and are incredibly harsh on your skin. They may (4):

  • Make the hair dry and brittle
  • Increase frizz
  • Cause chemical burns and injuries
  • Cause dandruff, hair loss, and thinning

A study also indicated a close link between hair relaxers and uterine leiomyomata (cancer) (5). However, further studies are required to confirm this hypothesis.


A hair relaxing treatment at the salon can cost about USD 200, while an at-home treatment costs about USD 20.

We hope this article has helped settle the keratin treatment vs. relaxer debate. Both the treatments can change your hair texture and make it appear smoother and manageable, depending on your natural hair texture and the strength of the chemical used. However, since both the treatments involve using chemicals and heat, they may damage the hair and skin and affect your overall health. Therefore, before opting for any one of them, consult a professional hairstylist to evaluate if the treatments are suitable for your hair type, texture, and quality.

Frequently Asked Questions

Is keratin good for relaxed hair?

Yes, keratin is good for relaxed or chemically treated hair. It may help restore the shine and smoothness of the hair.

Does keratin straighten black hair?

Yes, keratin works on black hair. You can go for keratin treatment if you want to straighten it and improve the shine and strength of your hair.

Does hair go back to normal after keratin treatment?

Yes, your hair will go back to normal when the effects of keratin treatment start fading. The results may last for 3 to 6 months.

Why is my hair frizzy after keratin treatment?

Your hair may become frizzy after keratin treatment if the stylist does not use enough product or use it incorrectly. Also, the high protein content of the product may result in frizzy hair.

Key Takeaways

  • Both keratin treatment and relaxers give hair a straight, frizz-free, and smooth look.
  • Keratin treatment minimizes frizz and gives lustrous hair, lasting for 3-6 months.
  • In relaxers, the structure of the hair is altered with special chemicals to give you silky, glossy hair.
  • Keratin treatment lasts for 3 to 6 months, while relaxers last for 6 to 8 weeks, depending on hair care habits.


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. Effects of the Usage of l-Cysteine (l-Cys) on Human Health
  2. Elevated formaldehyde concentration in “Brazilian keratin type” hair-straightening products: a cross-sectional study
  3. Hair-Smoothing Products That Release Formaldehyde When Heated
  4. Chemical Hair Relaxers Have Adverse Effects a Myth or Reality
  5. Hair Relaxer Use and Risk of Uterine Leiomyomata in African-American Women
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Ramona is an editor at StyleCraze. Prior to that, she authored over 200 articles on skin and hair care. She... more

Dr. Rinky Kapoor

Dr. Rinky Kapoor is the co-founder and director of The Esthetic Clinics. She is also the co-founder of a patented... more