Which type of chemical solution is required for restructuring coarse, resistant hair with a strong compact cuticle?

• A. Mildly acidic
• B. Neutral
• C. Mildly alkaline
• D. Highly alkaline

Answer: (D)

Restructuring hair hinges on getting the chemical agents to the cortex to break and then reform bonds, and that requires the cuticle to open up enough for penetration. Coarse, resistant hair with a strong, compact cuticle presents a tight barrier, so you need a high level of swelling to let the restructuring chemicals reach the cortex. A highly alkaline environment raises pH sufficiently to lift and swell the cuticle scales, increasing porosity and allowing the reducing or restructuring agents to penetrate and work effectively. In contrast, mildly alkaline, neutral, or mildly acidic solutions don’t provide enough cuticle swelling for this type of hair, so they’re not adequate for achieving the desired restructuring. Use of a highly alkaline solution, with proper timing and safety precautions, enables the disulfide bonds to be broken and reformed into the new shape.