What are sodium hydroxide relaxers commonly known as?

Sodium hydroxide relaxers are commonly known as lye relaxers because they contain sodium hydroxide as their primary active ingredient. This chemical is highly effective in breaking down the protein structure of the hair, leading to the desired straightening effect. The term "lye" references the caustic nature of sodium hydroxide, which effectively alters the hair's structure by breaking the disulfide bonds that give hair its natural curl or wave.

While other types of relaxers exist, such as thio relaxers that are based on ammonium thioglycolate, hydrolyzed relaxers that typically contain proteins, and non-lye relaxers that utilize different active ingredients like guanidine hydroxide, they do not contain sodium hydroxide. Thus, the specific association of sodium hydroxide with the term "lye relaxers" makes it the correct answer in this context. Understanding this distinction is important for cosmetologists when recommending products based on clients' hair types and needs.