Chemical Structure of a Hair Relaxer

Hair relaxers, so called for their ability to soften and relax the hair's natural curl, can be used at home or in the salon. Results vary from stick straight strands to loosened curls, depending on your hair's texture, coarseness and whether it's been chemically treated.

Hair Structure

Each hair strand is composed of keratin, which is made up of interwoven protein helices. Cysteine (an amino acid) and keratin bond to hold the hair shaft together in a strong but flexible manner called cross-linking. This disulfide bonding determines a hair's curliness.

Function

Hair relaxers break the hair's disulfide bonds in order to "permanently" straighten or loosen curls. Chemicals in relaxers create longer lasting effects than flat irons and blow dryers because they penetrate the hair's cortex and alter the durable chemical structure within.

Ammonium Thioglycolate

Ammonium thioglycolate is a basic reducing chemical compound (NH4+HSCH2COO) and the primary ingredient in most relaxing treatments. According to chemist Charles Ophardt of Elmhurst College, the agent is used to "reduce and rupture some of the disulfide cross-links" so the bonds can shift positions.

Sodium Hydroxide

Sodium hydroxide (NaOH), commonly known as "lye," is another reducer or base which breaks the hair's chemical bonds. It is a harsh chemical that softens then swells the hair's fibers, according to HairBoutique.com.

Warnings

The high alkaline content of these bases can damage hair if not administered properly. Their concentrations range from 5 to 10 percent in relaxers, and the higher the concentration, the faster they break bonds, but the more quickly they damage hair.

References

• Elmhurst College: Virtual Chembook: Permanent Hair Wave
• Hair Boutique: Chemical Hair Relaxers: Myths & Magic
• Cornell University: Variety of Chemicals in Hair Relaxers Untwist Strands