Which substance is not compatible with a perm and may cause uneven curl, discoloration and breakage?

• A. Metallic Salts
• B. Water
• C. Alcohol
• D. Glycerin

Answer: (A)

Metallic salts introduce metal ions that react with the chemicals used in a perm. During a perm, a reducing agent breaks disulfide bonds in the hair, and an oxidizer then re-forms them to set the curl. Metal ions can catalyze unwanted side reactions, create deposits, or alter the balance of the chemical reactions across the hair, which leads to an uneven curl, discoloration, and potential breakage where those reactions are concentrated. Water is just a solvent and doesn’t add reactive ions, while alcohol and glycerin are not known to cause this specific incompatibility in standard perm chemistry. So, metallic salts are the substance that can cause these issues.