Which chemical is commonly used in permanent wave solutions?

Ammonium thioglycolate is commonly used in permanent wave solutions due to its effectiveness in breaking disulfide bonds in hair. This chemical serves as a reducing agent that allows the hair to be reshaped when it is wrapped around perm rods. By breaking the natural bond structure of the hair, ammonium thioglycolate enables stylists to create curls or waves that can last for several months.

The use of ammonium thioglycolate in permanent waving is particularly valued for its ability to provide more manageable curl formation compared to other chemicals. It also has a lower pH level than some alternatives, making it somewhat less damaging to the hair's structure, given proper application and care.

In contrast, the other chemicals listed have different purposes or effects. Cetyl alcohol is primarily a fatty alcohol used as an emulsifier or thickening agent in cosmetic formulations, not as a curling agent. Sodium hydroxide is a strong alkaline agent used in certain types of chemical relaxers rather than perms, as it straightens hair rather than curling it. Glyceryl monostearate is commonly used as an emulsifying agent in creams and lotions and has no role in the permanent waving process. Thus, ammonium thioglycolate stands out as the