Which ingredient is commonly found in hair relaxers?

Sodium hydroxide is commonly found in hair relaxers due to its strong alkalizing properties, which are essential for altering the hair's structure. This ingredient works by breaking the disulfide bonds in the hair, allowing the hair to be reshaped and straightened. The alkaline nature of sodium hydroxide raises the pH of the hair, enabling better penetration into the hair shaft and facilitating the relaxing process.

In contrast, glycerin serves as a humectant and moisturizer but does not have the properties needed for hair relaxing. Cocamidopropyl betaine is primarily a surfactant and is used for cleansing and foaming but does not affect the hair structure in the same way. Hydrolyzed protein is often added for strengthening and moisturizing benefits, but it does not play a role in the chemical alteration of hair texture. Thus, sodium hydroxide is specifically selected for its effectiveness in achieving the desired straightening effect in hair relaxers.