What is the effect of sodium hydroxide in hair relaxers?

The effect of sodium hydroxide in hair relaxers is primarily that it breaks disulfide bonds, which are the structural bonds in the hair that contribute to its shape and texture. Hair is made of a protein called keratin, and the curls or waves in hair are due to these disulfide bonds. When sodium hydroxide is applied, it penetrates the hair shaft and alters the disulfide bonds, effectively allowing the hair to be reshaped into a straighter style. This chemical process is essential to the functionality of a relaxer, as it enables the manipulation of the hair structure to achieve the desired straightening effect.

The other options do not accurately represent the action of sodium hydroxide in hair relaxers; it doesn’t add moisture, enhance color, or condition the hair in a positive sense. Instead, it can often lead to dryness or damage if not used properly, which is why aftercare and conditioning are important following the use of a relaxer.