Which chemical is commonly used in the perming process?

Ammonium thioglycolate is a key ingredient in the perming process because it is a strong reducing agent that breaks down the disulfide bonds in the hair's keratin structure. This alteration allows the hair to be reshaped, enabling the establishment of curls or waves. When the hair is treated with ammonium thioglycolate, it softens, which allows the stylist to mold it into the desired shape using rods or other tools. Once the hair is in the desired configuration, a neutralizer is applied to reform the disulfide bonds in their new shape, effectively setting the perm.

The other chemicals mentioned are used for different purposes. Hydrogen peroxide, for instance, is commonly found in hair bleaching and lightening processes, not in perming. Glycerin is often used as a moisturizer or emollient in hair products but does not have a function in altering the internal structure of the hair for curls. Sodium chloride is typically used in salt solutions or as a preservative but does not impact the hair's structural chemistry as required in perming.