What is a common use for sodium hydroxide in hair treatments?

Sodium hydroxide is commonly used in hair treatments as a hair relaxer. It works by breaking down the protein structure of the hair, specifically the disulfide bonds of keratin. This chemical alteration allows curly or wavy hair to be transformed into a straighter texture through a process known as chemical relaxing. The concentrated formula of sodium hydroxide effectively straightens the hair, making it easier to manage for individuals seeking to lessen frizz or curl in their hairstyles.

In contrast, color enhancement and moisture retention typically involve different ingredients tailored to either deposit color or hydrate the hair, rather than altering its fundamental structure. Scalp soothing products are designed to calm irritations or dryness but do not have the same chemical effects as sodium hydroxide. Thus, sodium hydroxide's primary role in hair relaxing stands out as a distinct function in the realm of hair care treatments.