Research Paper: Comparison of Hair Damage Based on Treatment Timing During Iron Permanent Wave Procedure

This study investigated the optimal timing for applying a hair conditioner during a permanent wave process to minimize hair damage. Four hair samples were treated at different times, and their tensile strength, hydration, thickness, and cuticle condition were analyzed using Atomic Force Microscopy. The sample treated in the middle of the process showed the best results, with 3% higher tensile strength than early-treated, 11% higher than late-treated, and 16% higher than untreated samples. It also had the lowest moisture loss rate and the healthiest cuticle structure. These findings suggested that mid-treatment application of conditioner could effectively reduce hair damage during permanent waving.