Which hair bonds are manipulated during perm and relaxer processes?

• A. Disulfide bonds in keratin; broken by reducing agents and re-formed by oxidizing agents in the neutralizer.
• B. Hydrogen bonds only.
• C. Peptide bonds in keratin.
• D. Salt bridges only.

Answer: (A)

Disulfide bonds between cysteine amino acids in keratin are the bonds that determine hair shape and are specifically targeted in perming and relaxing. A reducing agent breaks these covalent S-S bonds, converting them to sulfhydryl groups so the hair can be reshaped on rods or into a straight form. After reshaping, an oxidizing agent in the neutralizer re-forms the disulfide bonds, locking the hair into its new configuration.

Hydrogen bonds and salt bridges can influence temporary reshaping, but they are not permanently changed to hold the new form, so they don’t drive the permanent set. Peptide bonds in keratin are the basic protein backbone and aren’t broken or reformed in these treatments. Thus the key bonds manipulated are disulfide bonds in keratin.