What characteristic defines thio relaxers?

Thio relaxers are defined by their formulation, which includes a specific type of thioglycolic acid or its derivatives. Unlike sodium-based lye relaxers, thio relaxers are categorized as "no-lye" relaxers, which significantly reduces the potential for irritation and damage to the hair and scalp. This characteristic allows hair professionals to provide a gentler option for clients seeking texture alteration without the harshness associated with traditional lye relaxers.

While thio relaxers can indeed have an alkaline nature, they may not necessarily be categorized solely by high pH and alkalinity. Additionally, it’s important to note that although some thio relaxers may have little or no ammonia, this is not a defining trait across all thio formulations. Also, the statement about having no chemical reaction on hair is incorrect because thio relaxers do initiate a chemical process that alters the hair's structure in order to achieve straightening. Therefore, the defining characteristic of thio relaxers being a "no-lye" relaxer distinguishes them from other relaxers and gives insight into their formulation and gentler application.