1. Perm dyeing: The perm potion contains a lot of ammonia alkali, and the chemical composition is the most harmful to the hair
2. Hair blower, electric splint, the temperature is above 120 degrees
3. Sea water: contains a lot of alkalies
4. Tap water: Contains disinfectant, sulfur copper.
5. Mechanical damage (such as scissors, razors, combs)
6. Sun, UV rays
7. Improper shampooing method or poor quality shampoo
