The Chemistry Behind Hair Dye and Lightening > 자유게시판

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Hair coloring and bleaching are popular beauty treatments that transform the appearance of hair, but behind the vibrant shades and lightened strands lies a complex scientific process.

Human hair gets its color from two types of melanin: eumelanin, which produces brown and black tones, and pheomelanin, which contributes to red and yellow hues.

The combination and concentration of these pigments determine your natural hair color.

Hair coloring products typically contain dyes that either deposit new color onto the hair or chemically alter existing pigments.

These non-permanent formulas don’t enter the hair extension wholesale suppliers cortex—they simply adhere externally and rinse away after several shampoo cycles.

To achieve lasting color, permanent dyes contain tiny molecules capable of slipping past the cuticle and into the hair’s inner layers.

The interaction between dye molecules and hydrogen peroxide triggers a polymerization reaction, trapping the new color permanently inside the hair shaft.

Lightening hair through bleaching is a far more destructive chemical intervention than standard coloring.

It uses hydrogen peroxide, often combined with ammonia, to break down the natural melanin inside the hair.

Peroxide swells the hair structure and chemically breaks melanin into harmless, transparent fragments.

This lightens the hair, but it also removes the hair's natural protective layer and can leave the hair feeling dry and brittle.

Each level of lightening increases porosity and fragility, making post-bleach conditioning not optional, but essential.

The pH level of hair coloring products is also critical.

A healthy hair shaft has a pH level that’s slightly acidic—typically between 4.5 and 5.5—to preserve its protective barrier.

Permanent dyes and bleaches are intentionally alkaline—often pH 8–9 or higher—to force the cuticle to swell and permit penetration.

The raised pH causes the cuticle scales to lift, creating pathways for dyes and bleach to reach the cortex.

Post-treatment acidic rinses or conditioners are crucial to reseal the hair and prevent color fade and moisture loss.

How well your hair absorbs color depends heavily on its porosity—the ease with which it takes in liquids and chemicals.

Damaged or processed hair has lifted cuticles and gaps in the cortex, making it a sponge for chemicals.

If porosity isn’t assessed, some sections may over-process while others remain under-treated.

Professionals often perform strand tests to predict how hair will react to a specific product.

Advances in hair color technology now integrate reparative components like ceramides, panthenol, and botanical extracts to reduce breakage.

Some products even include antioxidants to help protect the hair from oxidative stress during the coloring process.

No matter how advanced the formula, changing hair color always involves breaking molecular bonds and restructuring the hair’s core.

Knowing how dyes and bleach work empowers you to choose smarter products and avoid costly mistakes.

Whether DIY or professional, understanding the process lets you avoid over-processing, reduce damage, and extend the life of your color.

Hair is not just a canvas—it's a living structure that responds to chemistry, and respecting that science leads to healthier, longer lasting results.