What chemical process is used to change the structure of hair during a perm?

The chemical process used to change the structure of hair during a perm is reduction. In hairdressing, the perm process involves the use of reducing agents, typically thioglycolic acid or ammonium thioglycolate, which break the disulfide bonds in the hair's keratin structure. By breaking these bonds, the hair can be reshaped around the curling rods used during the perming process.

After the desired curl pattern is achieved and the hair is set, a neutralizing solution is applied. This solution helps to reform the disulfide bonds in their new configuration, "locking" in the new curl. While neutralization plays a critical role in completing the perm process, it is the reduction that initiates the permanent alteration of the hair's structure.

Understanding the significance of reduction is vital in the perming process, as it directly relates to the ability to create lasting curls or waves in the hair.