California Cosmetology Written ExamChemical Texture ServicesMedium
A client with virgin, resistant hair chooses a sodium hydroxide relaxer for permanent straightening. Which chemical process permanently alters the disulfide bonds during this service?
- AOxidation
- BLanthionization
- CReduction
- DSaponification
Show answer & explanationAnswer & explanation
Correct answer: B. Lanthionization
Hydroxide relaxers like sodium hydroxide permanently convert disulfide bonds into lanthionine bonds through a process called lanthionization, which cannot be reversed like thio relaxer bonds.
Why the other options are wrong
- A. Oxidation is used to neutralize thio-based texture services, not hydroxide relaxers.
- C. Reduction is the mechanism used by thio (ammonium thioglycolate) relaxers, not hydroxide relaxers.
- D. Saponification is a soap-making reaction unrelated to hair chemistry.
Lanthionization
The irreversible chemical process by which hydroxide relaxers convert disulfide bonds into lanthionine bonds, permanently straightening hair.
- Occurs with sodium, lithium, and guanidine hydroxide relaxers
- Bonds cannot be rebuilt, unlike thio relaxer bonds
- Requires careful strand testing due to permanence
Memory trick: 'Lanthionization = Lasting change, no going back'