What is the primary ingredient in most hair relaxers?

Sodium hydroxide is the primary ingredient in most hair relaxers due to its strong alkaline properties, which work effectively to break down the protein structure of the hair, allowing for the smoothing and straightening process. By raising the pH level of the hair, sodium hydroxide opens the cuticle, enabling the relaxing agent to penetrate and modify the hair's natural texture.

In the context of hair relaxing treatments, sodium hydroxide is well-known for its efficiency in effectively relaxing tightly coiled or textured hair, making it a popular choice among many professionals in the beauty industry. Its potency requires careful application and typically only trained professionals should use it, as improper use can lead to hair damage or changes in the scalp's condition.

Other ingredients mentioned serve different purposes in hair care and treatments. For example, ammonium thioglycolate is commonly found in perms rather than relaxers, and calcium carbonate and sodium chloride do not play a major role in the hair relaxing process, making them less relevant in the context of this question. The strong alkaline nature of sodium hydroxide makes it the go-to ingredient for achieving smooth, relaxed hair effectively.