Which reducing agent is most commonly used in permanent waving?

Which reducing agent is most commonly used in permanent waving?

• A. Hydrogen peroxide
• B. Ammonium thioglycolate (ATG)
• C. Sodium bromate
• D. Sodium hydroxide

Answer: (B)

Permanent waving relies on first breaking and then reforming the hair’s disulfide bonds to hold a new shape. The reducing agent in the waving solution does the job of opening those bonds so the hair can be wrapped around rods and reshaped. The most commonly used reducing agent for this step is ammonium thioglycolate. It effectively reduces the sulfur-sulfur bonds in the hair, allowing the strands to take on a new configuration as they’re wrapped. After shaping, a neutralizer—typically hydrogen peroxide—oxidizes the thiol groups back to disulfide bonds, locking in the curl or wave. Hydrogen peroxide is an oxidizer, not the reducing agent, so it isn’t the best answer for what actually reduces the bonds. Sodium bromate can act as an oxidizer in some systems, but not the standard reducing agent. Sodium hydroxide is a strong base used to raise pH in alkaline perms or relaxers, not to reduce disulfide bonds.

Permanent waving relies on first breaking and then reforming the hair’s disulfide bonds to hold a new shape. The reducing agent in the waving solution does the job of opening those bonds so the hair can be wrapped around rods and reshaped. The most commonly used reducing agent for this step is ammonium thioglycolate. It effectively reduces the sulfur-sulfur bonds in the hair, allowing the strands to take on a new configuration as they’re wrapped.

After shaping, a neutralizer—typically hydrogen peroxide—oxidizes the thiol groups back to disulfide bonds, locking in the curl or wave.

Hydrogen peroxide is an oxidizer, not the reducing agent, so it isn’t the best answer for what actually reduces the bonds. Sodium bromate can act as an oxidizer in some systems, but not the standard reducing agent. Sodium hydroxide is a strong base used to raise pH in alkaline perms or relaxers, not to reduce disulfide bonds.