What chemical is commonly used in relaxers to straighten hair?

Sodium hydroxide is commonly used in hair relaxers due to its strong alkaline properties, which allow it to effectively break down the protein structure of curly or wavy hair. This chemical works by opening the hair's cuticle and altering the disulfide bonds within the hair shaft, ultimately leading to a smoother and straighter texture. The high pH level of sodium hydroxide helps in maximizing this straightening process, making it a preferred choice for many professional hair relaxer formulations.

Other chemicals mentioned, such as calcium hydroxide and ammonium thioglycolate, are used in different types of chemical treatments, but sodium hydroxide is specifically known for its effectiveness in hair relaxing. Hydration agents like hydrogen peroxide play a different role, primarily in lightening hair rather than straightening it. Thus, sodium hydroxide is key for those seeking to achieve straight hair through a chemical relaxer treatment.