Which chemical is commonly used in permanent waves?

Ammonium thioglycolate is commonly used in permanent waves because it acts as a reducing agent that breaks down the disulfide bonds in the hair's keratin structure. This process allows the hair to be reshaped and given a new permanent curl or wave pattern. The effectiveness of ammonium thioglycolate in creating stable, long-lasting waves makes it a popular choice in the perming process.

Other chemicals listed have different roles or purposes in hair treatments. Sodium hydroxide is typically associated with relaxers used to straighten hair rather than creating waves. Glyceryl monothioglycolate is another reducing agent, but it's more commonly found in milder formulations for perms and is not as widely used as ammonium thioglycolate. Hydrogen peroxide is primarily used as an oxidizing agent in hair bleaching processes, not for creating permanent waves. Understanding the specific actions of these chemicals helps in mastering their application in cosmetology practices.