What is keratin hair straightening?

Keratin hair straightening is a semi-permanent method of hair straightening. This is usually preferred in hair that has been damaged, weakened and become lustreless with use of chemicals. Keratin or cysteine hair treatment are milder than permanent hair straightening or rebonding techniques. These treatment add shine, reduce frizziness and improve manageability in damaged hair.

Keratin hair straightening is a relatively newer method of hair straightening. It is also known by various other names like Keratin Smoothening therapy or Brazilian Keratin Straightening or Brazilian blowout. This technique was initially developed in Brazil.

How does keratin hair straightening work?

Straightening of hair requires breaking and rearranging of different bonds (hydrogen/salt linkages/covalent disulphide bonds) present between peptide chains of hair shaft.

Permanent hair straighteners disrupt and rearrange the disulphide bond between the hair peptides. This has been discussed in our previous post.

Semi-permanent hair straighteners have aldehyde groups (formaldehyde) that form cross-links with hair protein at specific regions keeping the hair in straight configuration. The bonds are stable for about 3-4 months and get broken through repeated washing cycles, allowing the hair to return to it’s previously curly state. As the disulphide bonds in hair are not disrupted, the perfect straightening of hair is not attained with keratin treatment. It is rather the hair smoothening therapy that smoothens the frizziness and curls rather them flattening them completely.

While formaldehyde forms cross-links with hair peptide and straightens them, the small molecules of hydrolysed keratin present in the active liquid or lotion penetrates the cuticle, helps to plump the hair and fill in the gaps. It strengthens the hair from within. Large molecules of keratin form a film on the surface of the hair, this has a overall conditioning effect. These all benefits are claimed by manufacturing companies though there is lack of scientific evidence that states that keratin penetrates shaft and strengthens it.

Step-by-step procedure of keratin hair straightening

• Hair is washed with a cleansing shampoo. Conditioner should not be applied
• Hair is dried completely, and then divided in sections.
• A coat of keratin treatment is applied on each section of hair from top to bottom.
• Coating of keratin treatment is blow-dried.
• Then, a flat iron is used to seal the solution on your hair and straighten them.

It takes 1.5 hours to 4 hours to complete the process depending on the length of your hair. You should not wash your hair or pin up your hair for next 3 days. After 3 days, you are required to wash your hair with recommended after care products only.

Advantages of keratin hair straightening

• It is less damaging to hair as compared to harsh chemicals used in rebonding technique
• This is usually preferred on chemically treated or damaged hair for smoothening
• Keratin treatment adds shine, smoothness and silkiness to your hair
• Keratin treatment is claimed to be a restorative therapy that strengthens your hair. However, there is lack of scientific data stating that keratin penetrates the hair strands and strengthens them.
• Less time taking than rebonding
• The effect of semi permanent hair straightening lasts for about 3 months, this gives you flexibility to change your hair style.

Disadvantages of keratin hair straightening

• Most of the side effects of Keratin therapy are due to formaldehyde. Exposure to formaldehyde solutions can cause contact dermatitis or skin irritation. Formaldehyde fumes produced while blow drying or flat iron straightening can cause burning of the eyes and throat, watering of the eyes, dry mouth, loss of smell, headache, feeling of grogginess, allergic reaction or precipitation of asthma.
• Repeated exposure to formaldehyde can cause blood cancer. While the clients don’t come in contact with formaldehyde regularly, but the hair stylists are at more risk. It is important for hair stylists to use proper protection gloves etc and maintain ventilation while using keratin- formaldehyde products.
• Effect is not permanent and wanes off in 3-4 months
• Like permanent hair straightening, hair does not completely straightens out or falls flat rather only frizziness of hair is tamed. It is a hair smoothening procedure
• Expensive
• Use of cheap low quality products or hot flat iron by inexperienced hairstylist may harm your hair. Also, the use of hot iron to seal keratin on to hair might rather cause long term damage to hair strands.

Keratin treatment has recently gone in disrepute due to the presence of formaldehyde, which is an irritant and carcinogenic chemical. To counter this claim, many brands came up with products that are ‘formaldehyde free’, or ‘low formaldehyde’. Such products should be used with special caution as some of them contain ingredients that turn into formaldehyde when they break down during the heat application. These ingredients include formalin, formic aldehyde, methanol, methylene glycol, methylene oxide, oxomethane and oxymethylene.

Cysteine is a natural amino acid present in hair strand. It is claimed that in cysteine hair straightening treatment, cysteine enters the hair shaft, fills the gap and strengthens the hair from within. These claims are made by companies manufacturing it and are yet not substantiated with scientific data. The long term safety data of cysteine therapy is yet to be evaluated. The effect of cysteine hair straightening usually lasts for 3 months. Cysteine hair straightening therapy deliver results similar to that of keratin therapy without the risk of formaldehyde exposure.

How does cysteine hair straightening work?

Glyoxylol carbocysteine is a new generation hair straightening agent that works similar to keratin hair straightening but is free from toxic effects of formaldehyde. It is a reaction product of glyoxylic acid, cysteine and acetic acid.

Glyoxylic acid has a functional aldehyde group that forms cross links with amino acids present in the hair shaft. This maintains the hair in a straight configuration for 3-4 months.

Advantages of cysteine hair straightening

Cysteine hair straightening therapy deliver results similar to that of keratin therapy, but without the risk of formaldehyde exposure. Thus, with cysteine, there won’t be any formaldehyde-related side effects, like contact dermatitis, skin irritation, or any long-term risk of cancer.