Quiz: Discover the Cause of Your Hair Loss

How Chemical Treatments and Heat Affect Hair

The hair you see growing out of your scalp is technically dead tissue composed primarily of the protein keratin.

Although it is dead, the structure and integrity of this tissue can be preserved or damaged depending on how you treat your threads.

Chemical treatments and excessive heat use can severely compromise hair structure, leading to breakage and damage that are often mistaken for hair loss.

It's important to understand the difference between true hair loss, where the hair falls out from the root along with the bulb, and breakage, where the hair breaks along its length.

Both result in less hair on the head, but the causes and treatments are different.

The structure of a hair strand is complex, with three main layers.

The outermost layer is called the cuticle, and it is formed by overlapping cells like fish scales or roof tiles.

When the cuticle is intact and the scales are tightly closed, the hair reflects light, appears shiny and smooth, and is protected.

The middle layer is called the cortex, and it contains most of the keratin protein, as well as the pigments that give hair its color.

The cortex is responsible for the strength, elasticity, and color of the hair strand.

The innermost layer is called the medulla, found mainly in thick hair strands, and its function is not yet fully understood.

Chemical procedures work by altering the protein structure of the hair to change its shape, texture, or color.

Hair straightening and relaxing treatments break disulfide bonds, which are chemical links that maintain the proteins in the cortex in a specific configuration.

By breaking these bonds and reforming them in a new position, the hair is permanently straightened.

Perms do the opposite, breaking the bonds and reforming them in order to create curls.

Hair coloring and bleaching work in different ways but are equally aggressive.

To dye hair, especially to colors lighter than the natural shade, the products need to open the cuticle, penetrate the cortex, remove the natural pigment, and deposit new pigment.

Bleaching processes use powerful oxidizing agents such as hydrogen peroxide to break down the melanin molecules that give hair its color.

This process is extremely damaging to the protein structure.

All these chemical procedures cause cumulative and irreversible damage to the hair structure.

The cuticle becomes lifted and damaged, leaving the cortex exposed and vulnerable.

The hair strands lose protein, become porous, lose elasticity, and become brittle.

Chemically treated hair is much more prone to breakage, especially when wet and more vulnerable.

When performed regularly without adequate recovery time between procedures, the damage accumulates.

Doing straightening and coloring treatments at the same time, or doing touch-ups too frequently, can lead to severe breakage.

In the most severe cases, the hair can break so close to the root that it looks like hair loss, but it is actually extreme breakage.

In addition to hair breakage, very strong chemical products applied improperly can cause chemical burns on the scalp.

These burns can damage the hair follicles on the surface of the skin.

If the damage is severe and repeated, it can even cause cicatricial alopecia, where the follicles are permanently destroyed and replaced by scar tissue.

This results in permanent hair loss in the affected areas.

Very strong relaxers, especially when left on the hair for an excessive amount of time or applied to previously treated hair, are particularly risky.

Using heat through tools like flat irons and hair dryers works differently but can also be very damaging.

Hair naturally contains water, and this moisture helps maintain the flexibility and elasticity of the strands.

When you apply very high heat, the water inside the hair strand literally boils, creating tiny bubbles of steam within the hair structure.

These bubbles can rupture the cuticle and create empty spaces within the cortex, structurally weakening the hair strand.

Temperatures above 180 degrees Celsius begin to degrade keratin proteins.

Many hair straighteners easily reach 200, 220, or even 230 degrees, especially when used at maximum temperature.

Using a flat iron daily at these temperatures causes significant cumulative thermal damage.

Hair dryers on very high heat, especially when held too close to the hair, also cause heat damage.

The problem worsens when heat is applied to wet hair, which is when the strands are most vulnerable.

Wet hair is temporarily weaker because the hydrogen bonds that help maintain its structure are temporarily broken.

Applying high heat to wet or damp hair maximizes damage.

It's important to make a distinction here: the occasional and careful use of heat tools, with thermal protection and at the appropriate temperature, does not cause irreparable damage.

The problem is daily or very frequent use without protection in excessively high temperatures.

Using a heat protectant creates a barrier that helps distribute heat more evenly and partially protects the cuticle.

Using lower temperatures, even if it takes a little longer, preserves the integrity of the hair strands.

Letting your hair air dry whenever possible gives your strands a break.

People who regularly undergo chemical treatments and also use heat daily are subjecting their hair to a perfect storm of damage.

Chemically straightened hair that is also flat-ironed daily, or bleached hair that is also blow-dried at maximum heat every day, suffers extreme damage.

In these cases, severe breakage is almost inevitable, and it can give the impression of a massive fall.

Another related but distinct type of damage is traction alopecia.

This happens when the hair is repeatedly pulled forcefully, causing mechanical stress to the follicles.

Very tight hairstyles such as very tight braids, very tight buns, very tight ponytails, or the use of heavy hair extensions that pull on the hair can cause this.

Constant stress on the follicles can permanently damage them, especially along the hairline and temples where the skin is thinner.

This type of alopecia is more common in people who wear these hairstyles daily for years.

Initially, hair loss is reversible if the stress is removed, but if it continues for a prolonged period, it can become permanent.

Now, if you keep your hair natural, without chemicals and without frequent use of heat, you are avoiding a major source of damage.

Natural hair can still break for other reasons, such as combing too aggressively, wearing hair ties that are too tight, or lack of hydration.

But overall, natural hair tends to maintain its structural integrity better.

It is possible to perform chemical procedures more safely by respecting certain principles.

Space out the procedures appropriately, allowing time for the hair to recover between applications.

Only do one type of chemical treatment at a time, avoiding overlapping straightening and coloring, for example.

Seek out qualified professionals who use quality products and appropriate techniques.

Invest heavily in reconstruction and hydration treatments to minimize damage.

Protect your hair from heat when using thermal styling tools.

But it's important to have realistic expectations: chemically treated hair will never be as strong as virgin hair.

If you are experiencing hair loss or breakage and you regularly undergo chemical treatments or use heat daily, consider giving your hair time to recover.

Sometimes a transition period, letting your hair be natural or drastically reducing treatments, allows you to see how much was damage and how much is real hair loss.