California Cosmetology Written ExamChemical Texture ServicesMedium
A client with extremely curly, resistant hair desires a permanent chemical straightening service that will provide the strongest, most enduring results. Which type of chemical relaxer would be most appropriate for this client?
- ASodium hydroxide relaxer
- BGuanidine hydroxide relaxer
- CAmmonium thioglycolate relaxer
- DLithium hydroxide relaxer
Show answer & explanationAnswer & explanation
Correct answer: A. Sodium hydroxide relaxer
Sodium hydroxide relaxers, also known as 'lye' relaxers, are the strongest and most effective relaxers for extremely curly, resistant hair. They have a very high pH (typically 12.5-13.5) and are designed to break a significant number of disulfide bonds, providing maximum straightening power.
Why the other options are wrong
- B. Guanidine hydroxide relaxers ('no-lye' relaxers) are considered milder than sodium hydroxide and are often used for clients with sensitive scalps, but may not provide the strongest results on extremely resistant hair.
- C. Ammonium thioglycolate relaxers ('thio' relaxers) are milder and better suited for fine, color-treated, or less resistant hair, offering less straightening power than hydroxide relaxers.
- D. Lithium hydroxide relaxers are strong 'lye' based relaxers, similar in strength to sodium hydroxide, but sodium hydroxide is generally considered the benchmark for the strongest results and is more widely available/used for this purpose.
Sodium Hydroxide Relaxers
The strongest chemical relaxers, also known as 'lye' relaxers, used for highly resistant, extremely curly hair.
- High pH (12.5-13.5) makes them very effective.
- Can cause significant scalp irritation and hair damage if misused.
- Do not require a separate neutralizer to rebuild bonds, but a neutralizing shampoo is essential.
- They break disulfide bonds permanently through a process called lanthionization.
Memory trick: Strongest Soda, Gentler Goo, Milder Thio.