Three Types of Hair Damage: Telling Chemical, Heat and Physical Damage Apart

2026.10.23Damage

1. Chemical damage (color, bleach, perm, straightening)

These treatments swell the hair with alkali and use oxidizing or reducing agents to change the internal bonds and melanin. CMC (lipids) washes out, some cystine bonds break and proteins are lost. Signs: the ends dry out most, and wet hair stretches and feels rubbery. The lighter the hair, the stronger the effect.

2. Heat damage (hair dryer, flat iron, curling iron)

Proteins change their properties at high temperatures (the same principle as an egg setting when cooked). Applying high heat to wet hair in particular turns the water inside into steam suddenly, which breaks down the structure. Signs: hair feels hard and coarse, shine is dull, and the ends look whitish and split. Common in people who use a flat iron at 180°C or higher every day.

3. Physical damage (friction, UV, dryness)

Rubbing with a towel, sleeping with wet hair, snagging when brushing, UV rays and dry air. The cuticle chips and lifts little by little. Signs: rough surface, tangling, split ends and breakage.

How to tell them apart

Condition	Likely cause
Stretches when wet, dry and rough when dry	Chemical (color, bleach)
Hard, coarse, whitish ends	Heat
Rough surface, split ends	Physical (friction, UV)

Approach to care

Chemical damage → treatments that replenish lipids and proteins; leave more time between salon treatments
Heat damage → use heat tools only on dry hair, lower the temperature, apply a heat-protecting leave-in first
Physical damage → press with a towel instead of rubbing, don't sleep with wet hair, protect from UV