NIC Barber Written (Theory) ExamScientific ConceptsHard
A client with extremely curly, coarse hair desires a permanent chemical relaxing service. The barber understands that this hair type has tightly packed cuticle layers and strong disulfide bonds. Which type of chemical relaxer would be MOST effective in permanently straightening this client's hair while minimizing potential damage?
- ALye-based relaxer (sodium hydroxide)
- BThio relaxer with a low pH
- CAmmonium thioglycolate with a high pH
- DAcid-balanced perm solution
Show answer & explanationAnswer & explanation
Correct answer: A. Lye-based relaxer (sodium hydroxide)
Lye-based (sodium hydroxide) relaxers are highly alkaline and are the strongest type of relaxer, designed to break strong disulfide bonds in extremely curly, coarse hair effectively. While potent, when used correctly by a skilled barber, they can provide permanent straightening for resistant hair.
Why the other options are wrong
- B. Thio relaxers with a low pH are generally weaker and often used for less resistant hair or as a 'thio-free' option, unlikely to be effective on extremely curly, coarse hair.
- C. Ammonium thioglycolate with a high pH is a common type of perm or relaxer, but sodium hydroxide is generally considered stronger and more effective for 'extremely curly, coarse' hair, which implies high resistance.
- D. Acid-balanced perm solutions are for creating curls or waves, not for straightening, and have a low pH that would not break strong bonds.
Sodium Hydroxide Relaxer
A highly alkaline chemical relaxer (also known as lye relaxer) used for permanent hair straightening.
- pH typically ranges from 10 to 14.
- Effectively breaks strong disulfide bonds in extremely curly/coarse hair.
- Requires careful application due to high potency and potential for scalp burns.
Memory trick: Lye for strong, Thio for mild.