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How does hair waving change cystine disulfide links in keratin?
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organosulfur compound
Examples of organosulfur compounds.
Hair waving utilizes a chemical process to alter the structure of keratin, the structural protein found in hair. The stability of keratin is largely due to cystine disulfide bonds, which link polypeptide chains together.1
The waving process involves two primary steps:
- Reduction: A mild reducing agent, such as thioglycol, is applied to the hair. This agent cleaves the cystine disulfide links, converting them into cysteine sulfhydryl (—SH) groups. This breakage of bonds dissociates the peptide chains, providing the flexibility necessary for the hair to be reoriented into a new shape.21
- Oxidation: Once the hair is set in the desired wave or curl, an oxidative treatment is applied. This process reoxidizes the sulfhydryl groups back into disulfide bonds, effectively "fixing" the hair in its new configuration.21