Damaged hair: Keratin, disulfide bonds and Olaplex

The chemical treatments we use for our hair in the salon or at home, such as bleaching, some types of dyes, perms or other types of treatments, damage the structure of the hair. Technically it is a denaturation of the proteins involved.
The structure of the hair is essentially composed of only one type of protein that we have all heard of: keratin. Keratin is therefore a chemical compound made up of amino acids (the building blocks of proteins).
When a protein such as keratin comes into contact with certain categories of chemical agents, such as oxidizing agents present in bleaching treatments, the bonds between the atoms of which it is composed tend to break. These breaks cause real damage to the hair structure, which in turn inevitably leads to a change in the shape of the curl, or to a stretching / lengthening.
The reason is pretty simple. Try to imagine a single protein as a long three-dimensional chain curled around itself. This curl is the reason behind why our hair is more or less curly.
As can be seen from the 2D graphic representation below, the breakage of the bonds (di-sulphide bridges) leads to a stretching of the keratin, macroscopically we can translate it with a stretching of the curl and the loss of its original shape.

What is a disulfide bridge?

Keratin, like any other protein, is made up of amino acids.
There is an amino acid called cysteine cointained in the keratin.
Cysteine plays a fundamental role in the structure of the hair, because this amino acid has in its chemical structure a "lateral arm" (called thiol or lateral thiol chain) which involves a sulfur atom.
In turn, this sulfur atom is capable of making a covalent bond with another sulfur atom belonging to a thiol group of another amino acid cysteine.
This ability to break bonds between sulfur atoms creates a structure in the hair that gives it strength.
In the following image you can see a schematic representation of a sulphide bond between two sulfur atoms (S) each belonging to a different amino acid. The bridge represents the physical / chemical bond between the two amino acids (each in turn belonging to a protein).
When these di-sulfide bonds are broken with the use of chemical agents, a free thiol group is created for each cysteine amino acid, where the sulfur binds to a free hydrogen atom (H), losing the ability to create a bridge with another atom of sulfur and thus causing a weakening of the hair with consequent loss of shape of the curl.
In the following image a representation of the bond no longer present, and of the presence of a free thiol group (HS - HS) for each of the two amino acids
Furthermore, the di-sulphide bridges give the hair a certain resistance to breakage. Inevitably, the fewer bridges there are, the less resistant the hair will be to break, which will have a greater tendency to break.
We also remember that: the bleaching treatments that are used to modify mainly another protein present in the hair, namely melanin, are not really selective towards the latter, so there will always be an unwanted stretching effect due to interaction between bleaching agent and keratin.

What is Olaplex?

Olaplex is a line of bond building treatments for hair repair. On CurlySelection you will find the two fundamental products for a complete reconstruction treatment in our “Intensive Treatments” category.
The active ingredient in Olaplex is a compound called bis-aminopropyl diglycol dimaleate, protected by at least two patents. We will not go into the details of the paternity of this active ingredient, we just need to know that it was developed by professional chemists with a long career behind them.
The small size of this compound allows it to penetrate deeply into the hair, only partially reconstructing the external cuticle and concentrating on the internal shaft.
Olaplex does not substantially change the porosity of the hair, it simply reconstructs the three-dimensional structure of the proteins, responsible, among other things, for the shape and resistance of the hair.
The bonds formed by bis-aminopropyl diglycol dimaleate are ionic bonds: the electrical voltage differential is exploited to adhere to the hair and thus simulate a sulfur bridge. This type of bond is not as strong as a true sulfur bridge, which is a covalent bond and for this reason the Olaplex treatment must be repeated over time with a personalized cadence based on the state of the hair, chemical treatments carried out and by realize in the future and so on. On CurlySelection we recommend an occasional use which can vary from 2 to 4 weeks or even more. Contact us at info@curlyselection.com to receive more personalized information based on your hair type and condition.
When to use it:
On chemically treated hair (bleaching, dyes with hydrogen peroxide and / or ammonia, perms, chemical straightening).
Excellent results are obtained if Olaplex is used simultaneously with the chemical treatment of the hair.
Good results are obtained, especially in terms of the shape of the hedgehog, even using it after chemical treatment.
Relevant and evident results could be obtained in case of hair previously damaged by dyes, sun, chlorine, heat.
When not to use it:
On slightly porous, slightly damaged, non-bleached, dyed or straightened hair, not burned by the sun, chlorine or heat (hairdryer and straightener), the application of the treatment does not produce any significant difference.
Most products that promise results such as Olaplex's (often the names contain Bond or Plex), contain silicones and / or hydrolyzed proteins. Both of these ingredients can temporarily help improve the appearance of the hair, but do not modify its structurein depth: only some hydrolyzed proteins manage to reach the inside of the hair, most of the proteins and silicones used in these products adhere to the sites. damaged cuticle with weak bonds, and are removed by washing (silicones need sulphates to be removed).

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