California Barber Written ExamHair Care ServicesMedium
A barber is applying an ammonium thioglycolate (thio) permanent wave solution to a client's hair. What is the primary chemical action of this solution on the hair during the waving process?
- ATo re-bond the disulfide bonds in their new shape.
- BTo swell the cuticle and break the disulfide bonds.
- CTo deposit artificial pigment into the hair cortex.
- DTo neutralize any remaining alkaline residue in the hair.
Show answer & explanationAnswer & explanation
Correct answer: B. To swell the cuticle and break the disulfide bonds.
Ammonium thioglycolate is an alkaline reducing agent that swells the hair cuticle, allowing it to penetrate the cortex and break the hair's natural disulfide (sulfur) bonds, making the hair pliable for reshaping.
Why the other options are wrong
- A. Re-bonding disulfide bonds is the function of the neutralizer, not the waving solution.
- C. Depositing artificial pigment is the function of hair coloring products, not permanent waving solutions.
- D. Neutralizing alkaline residue is part of the post-perm rinsing or conditioning, not the primary action of the waving solution itself.
Thio Perm Solution Action
Ammonium thioglycolate (thio) perm solutions act as reducing agents, swelling the cuticle and breaking the hair's internal disulfide bonds to allow for reshaping.
- Alkaline pH.
- Breaks disulfide bonds.
- Softens and makes hair pliable.
Memory trick: THIO breaks BONDS, making hair BEND.