Chemical Damage

Understanding Chemical Damage

Chemical damage to hair is a common concern, often resulting from various salon treatments designed to alter hair’s appearance. These processes fundamentally change the hair's internal structure, and when not performed correctly or when hair is over-processed, they can lead to significant weakening and deterioration of the hair fiber.

How Hair Works

To understand chemical damage, it's essential to grasp the basic structure of hair. Hair is primarily composed of a protein called keratin. Each strand has three main layers:

• Cuticle: The outermost layer, consisting of overlapping, scale-like cells that protect the inner layers. A healthy cuticle lies flat, reflecting light and contributing to shine.
• Cortex: The middle layer, which makes up the bulk of the hair fiber. It contains melanin (which gives hair its color) and keratin proteins arranged in long chains, providing strength and elasticity.
• Medulla: The innermost core, present in some hair types but not all, and its exact function is not fully understood.

Chemical treatments primarily affect the cuticle and cortex.

Common Chemical Processes That Cause Damage

Several popular hair treatments involve chemical alterations that can lead to damage:

• Hair Coloring and Bleaching: These processes involve opening the cuticle to deposit or remove pigment from the cortex. Bleaching, in particular, uses strong alkaline chemicals (like ammonia) and an oxidizing agent (like hydrogen peroxide) to break down melanin. This process can significantly weaken the disulfide bonds within the keratin structure, leading to brittleness and breakage. Permanent hair dyes also utilize similar chemical reactions to alter color.
• Perming and Relaxing/Straightening: Perming (creating curls) and relaxing or straightening (making hair straight) involve breaking and reforming the disulfide bonds in the cortex. Perm solutions typically use ammonium thioglycolate to break bonds, followed by a neutralizer (oxidizing agent) to reform them into a new shape. Relaxers, often containing sodium hydroxide (lye) or guanidine carbonate (no-lye), permanently break these bonds, making hair straight. Improper application, over-processing, or overlapping treatments on previously processed hair can severely compromise the hair's integrity.
• Keratin Treatments: While often marketed as restorative, some keratin treatments use chemicals like formaldehyde (or formaldehyde-releasing agents) which, when heated, create a chemical coating that smooths the hair. While this can temporarily improve appearance, some formulations can weaken the hair over time or if applied incorrectly.

Signs and Symptoms of Chemical Damage

Damaged hair exhibits several characteristic signs:

• Dryness and Roughness: The cuticle becomes raised and porous, leading to moisture loss and a rough texture.
• Frizz and Flyaways: An unsealed and damaged cuticle prevents hair from lying smoothly.
• Breakage and Split Ends: Weakened bonds in the cortex make hair fragile and prone to snapping, particularly when wet or styled. The ends of the hair may split due to the loss of integrity.
• Dullness and Lack of Shine: The roughened cuticle scatters light rather than reflecting it, making hair appear lifeless.
• Elasticity Loss: Healthy hair has a degree of elasticity. Chemically damaged hair may feel gummy when wet and stretch excessively before breaking, or it may have very little stretch at all.
• Color Fading: For color-treated hair, a compromised cuticle struggles to retain pigment, leading to faster color fade.

Preventing Chemical Damage

Prevention is key when it comes to chemical treatments:

• Professional Application: Always seek experienced and reputable stylists for chemical services. They understand hair chemistry and can assess your hair's condition and history.
• Strand Tests: A stylist should perform a strand test before a chemical service to determine how your hair will react and to identify appropriate processing times.
• Honest Hair History: Provide your stylist with a full and honest history of your hair's chemical treatments and any allergies.
• Limit Overlapping Processes: Avoid applying chemical treatments to hair that has already been processed, as this can lead to severe damage.
• Appropriate Aftercare: Use products specifically formulated for chemically treated hair. These often contain ingredients designed to strengthen bonds, moisturize, and seal the cuticle, such as protein-rich conditioners and masks.
• Manage Expectations: Understand that certain hair types or conditions may not tolerate aggressive chemical treatments without significant risk of damage.

Treating Chemically Damaged Hair

While damage cannot be entirely reversed, its appearance and health can be significantly improved with consistent care:

• Gentle Cleansing: Use a sulfate-free shampoo to avoid stripping natural oils and further dehydrating hair.
• Deep Conditioning: Incorporate regular deep conditioning treatments or hair masks to provide intense moisture and nourishment.
• Protein Treatments: Products containing hydrolyzed proteins (e.g., keratin, wheat protein) can temporarily patch up gaps in the cuticle and cortex, offering strength and reducing breakage. Use these sparingly, as too much protein can make hair stiff.
• Leave-in Conditioners: These provide ongoing moisture and protection throughout the day.
• Heat Protection: Minimise heat styling. When using heat tools, always apply a heat protection product to reduce further stress on already weakened strands.
• Regular Trims: Removing split ends is crucial as they cannot be repaired and will continue to travel up the hair shaft, causing more damage.
• Bond-Building Treatments: Some products contain ingredients designed to help rebuild and protect the internal disulfide bonds, either at home or as an in-salon service.

The pH Factor

Many chemical treatments are highly alkaline. Healthy hair and scalp typically have a slightly acidic pH, ranging from 4.5 to 5.5. Alkaline chemicals cause the hair cuticle to swell and open, allowing chemicals to penetrate. While necessary for processing, prolonged alkalinity or insufficient re-acidification can leave the cuticle compromised and porous, contributing to damage. Look for aftercare products that are pH balanced or slightly acidic to help close the cuticle and restore hair's natural state.