Are you looking to change up your hairstyle and decided to try highlights? Or perhaps you've been avoiding heat for a while and wanted to see how your hair would look straight, but now your curls look more like waves or your hair won't curl at all. To better understand why this happens, let's delve into the chemistry of hair.
Hair chemistry simplified.
It all begins with the smallest unit of matter, atoms. These atoms link up by sharing electrons to become amino acid molecules. When amino acid molecules join together end to end they form a peptide bond which is the backbone of all protein. These bonds connect thousands of amino acids side to side to form chains, ultimately becoming the keratin protein of hair.
These protein chains are then held together by four side bonds and they each have an specific purpose in building the hair structure.
Hydrogen bond: these bonds are individually weak, but they are so abundant in the protein of hair that they help organize the protein chains and give hair its shape. This bond can be easily broken by heat or water.
Salt bond: just like hydrogen bonds, salt bonds are not particularly strong but because there are millions of salt bonds in the hair structure, they also help organize protein chains and can be weakened by water. They react to Ph changes so any strong alkaline or acidic solution will break these bonds too. When hair is saturated with water all these bonds temporarily break and the hair becomes pliable. This is why we are able to reshape it by applying tension and heat.
Disulfide bond: while hydrogen and salt bonds allow us to physically change hair, disulfide bonds are chemical bonds, and they give hair it’s strength. They are one of the strongest naturally occurring bonds in the world. The protein in hair contains the amino acid cysteine which oxidizes to cystine leading to the formation of the disulfide bond. This formation happens when two sulfur atoms link and create a strong connection that is permanent but that could be broken by external actions.
When disulfide bonds break the keratin structure comes apart and hair becomes weak. High temperatures applied directly and consistently to the hair may alter the chemical structure of the hair. Chemical processes like perms and relaxers use a reducing agent to break the disulfide bonds and reshape the hair structure. Other chemical processes like coloring the hair use an oxidizing agent to break the disulfide bond. Once the disulfide bond is disrupted it will never be as strong as it originally was.
So, why isn't your hair curly anymore? because the hair structure has been compromised and some of the disulfide bonds have broken. The keratin chains come apart which weakens the hair and makes it lose its elasticity.
What can I do if this happens? damage to the hair structure is irreversible, but there are products called "Bond builders" that are able to penetrate hair at a molecular level and can create an artificial disulfide bridge. This bridge relinks the broken disulfide bonds giving the hair a healthy appearance, restoring elasticity and strength.
The most trusted brands right now are Olaplex N3 and Curlsmith Bond Rehab salve.
Olaplex is widely used by hairstylist to prevent damage while bleaching. They offer a take home version that is highly recommended to use after getting any chemical process done to the hair.
Curlsmith Bond rehab salve takes it a little farther by including protein in its formulation. Remember, your hair is made up primarily of keratin protein, so this product will act as a two in one strengthening treatment by creating new bond links while boosting the protein content of the hair.