After twenty years working with hair fiber in fashion, photo shoots, and private salons, I’ve learned to distinguish two types of damaged hair.
The first type is immediately visible: dull, brittle, dry, sometimes excessively elastic. In professional jargon, it's often referred to as "rubbery" hair, a sign of severely weakened keratin.
The second type is more insidious. The hair still looks okay. Cosmetic treatments keep it presentable. Yet, structural damage progresses silently until the fiber breaks clean off.
Understanding, biologically, mechanically, and chemically, why hair gets damaged is the first step to choosing truly effective care.
The Lipid Film: The First Line of Defense
The surface of the hair is covered by a natural hydrophobic lipid film. This film protects the fiber against water, pollution, and friction, while ensuring uniform light reflection, which gives hair its natural shine.
Every wash, every heat styling session, every coloring treatment gradually degrades this protective layer.
When the lipid film is altered, the hair's behavior changes: it snags, becomes frizzy, loses its luster, and absorbs moisture unevenly.
These aren't yet visible damages. These are the first signals.
The Cuticle: The Lifting Armor
Beneath the lipid film is the cuticle: a layer of keratin scales that protects the inner cortex.
When the cuticle is intact and perfectly flat, the hair is smooth, shiny, and resistant. When it lifts, the fiber becomes rough, porous, and vulnerable.
Heat, alkaline treatments, harsh surfactants, and mechanical friction gradually weaken this structure.
Simply rubbing a towel on wet hair remains one of the most underestimated causes of cuticular damage.
An open cuticle exposes the cortex. And that's when deep structural damage begins.
The Cortex: Where True Degradation Happens
The cortex accounts for nearly 85% of hair's mass. It determines the mechanical strength, elasticity, and overall mechanical hold of the fiber.
It is made up of keratin microfibrils held together by various chemical bonds: disulfide, hydrogen, and ionic.
Bleaching and chemical treatments directly target these bonds to alter the pigment or structure of the hair.
Repeated over time, these processes gradually weaken the hair fiber's internal architecture, leading to breakage, loss of elasticity, and excessive porosity.
Main Causes of Damaged Hair
1 — Heat
Hair dryers, straighteners, and curling irons are often used without adequate heat protection.
Between 180 and 220 °C, partial denaturation of keratin proteins occurs rapidly. Repeated daily for years, it becomes structurally significant.
2 — Coloration and Bleaching
Even when done under good conditions, colorations alter the hair fiber.
The question isn't about stopping colorations, but about adopting a consistent repair protocol between treatments.
3 — Harsh Surfactants
Some shampoos remove not only residues but also essential natural lipids that protect the hair fiber.
Overly aggressive cleansing gradually becomes destructive.
4 — Mechanical Friction
Brushing wet hair, towel friction, cotton pillowcases: these repeated micro-frictions generate daily, invisible yet cumulative damage.
5 — Pollution and UV
Oxidative stress, induced by free radicals, gradually degrades proteins and natural lipids.
This factor remains largely underestimated in home routines.
What "Repairing Hair" Actually Means
True repair is not about masking damage with silicones or temporary film-forming agents.
It involves restoring natural lipids, strengthening keratin bonds, and improving cuticular cohesion.
These are biological and biomimetic mechanisms.
This is precisely the logic behind BLOWN hair products: to act at the original level of the fiber to restore resistance, suppleness, and shine in a uniform manner.
FAQ
Can severely damaged hair regenerate?
Yes, to a large extent. Structural damage can be significantly mitigated through targeted reparative active ingredients and a consistent routine.
However, overly degraded ends still need to be trimmed regularly to prevent the spread of breakage.
Dry hair and damaged hair: are they the same thing?
No.
Dry hair primarily lacks hydration. Damaged hair exhibits structural damage to the cuticle or cortex.
Both issues require different solutions.
Can you use a straightener without damaging your hair?
Temperature, frequency, and, most importantly, heat protection play a central role.
Appropriate heat protection, combined with a temperature consistent with the hair's nature, considerably limits cumulative damage.