Chemical-soaked hair and insufficiently washed hair are more susceptible to thermal denaturation. Elasticity is 20-30% on dry hair, 50-60% on wet hair, and 70% when wet with perm, meaning hair stretches better when wet. The denaturation of keratin changes when it is placed at a specified temperature for 10 minutes, with denaturation starting at 70°C at 70% humidity and 60°C at 97% humidity. Therefore, it is recommended to keep the temperature below 60°C to avoid damaging the hair.