When hair is burned, the outside layers of the hair, known as the cuticle, burn away leaving the hair's cortex exposed. If more heat is applied to the damaged hair, it becomes brittle and breaks off completely.
Once the hair's cortex is exposed, the hair begins to soak up moisture from the surrounding air to compensate for its loss. The additional moisture causes the hair to become frizzy. To help heal hair that has been burned by appliances such as curling irons, blow driers and flatirons, towel-dry the hair after washing it. Next, apply a heat protectant spray that contains panthenol to the hair, ensuring that the damaged and weakened areas are coated well before blow-drying the hair.
To prevent hair from burning while using a styling appliances, use a hairdryer with powerful airflow to reduce the hair's exposure to the heat and the amount of drying time that is required. A nozzle attachment should also be used in order to maintain a safe distance between the hair and the dryer's hot metal coils. When using a flat iron, only go over each section of hair once to prevent excess heat exposure. The temperature of the flat iron should be set to no more than 360 degrees Fahrenheit for fine hair and 410 degrees Fahrenheit for thick hair to prevent burning.