Neutralization in permanent waving also contributes to rebuilding which bonds?

• A. Disulfide bonds
• B. Hydrogen bonds
• C. Salt bridges
• D. Van der Waals forces

Answer: (A)

Neutralization in a perm locks in the new shape by restoring the covalent cross-links that define hair structure. After the reducing agent breaks the hair’s disulfide bonds, the hair can be reshaped. The neutralizer then oxidizes the resulting thiol groups, reforming disulfide bonds and stabilizing the curl. Hydrogen bonds and other weaker interactions can reform with moisture and pH changes, but they don’t provide the permanent hold like disulfide bonds do.