Which ingredient is used in a perm solution to break down hair bonds?

The ingredient that is used in a perm solution to break down hair bonds is ammonium thioglycolate. This chemical compound is a powerful reducing agent that works by breaking the disulfide bonds in the hair's keratin structure. This process is essential in perming because it allows the hair to be reshaped into new curls or waves. Once the hair is treated with ammonium thioglycolate, it becomes malleable, enabling the stylist to wrap it around curlers or rods to achieve the desired hairstyle.

Ammonium thioglycolate is specifically formulated for this purpose, and its effectiveness as a reducing agent makes it a staple in perm solutions. The other ingredients listed perform different functions: cetyl alcohol is primarily used as an emollient or thickener in cosmetic formulations; glyceryl monothioglycolate serves a similar purpose to ammonium thioglycolate but is less commonly used in traditional perm solutions; and hydrogen peroxide is often used as a developer in hair coloring processes but does not play a role in breaking down hair bonds during perming.