hair structure and pH

Hair is a sophisticated biomaterial composed of millions of interwoven keratin chains made of amino acids. These chains are held together by disulfide, hydrogen, and ionic bonds, giving hair strength and elasticity.

A balanced pH is crucial for maintaining these bonds and keeping hair healthy, so when the pH of its environment shifts more acid or alkaline, it can significantly affect its structure:

In an acidic environment (low pH):

• Chemical bonds tighten

• Hair swelling decreases

• Elasticity improves

• Outer cuticle becomes smoother and flatter

• Hair can appear shinier and more manageable

• Color is locked in, minimizing unwanted shifts
  
  

In an alkaline environment (high pH):

• Disulfide, hydrogen, and ionic bonds can be disrupted

• Hair swells and becomes more porous

• Elasticity decreases

• Outer cuticle lifts or becomes damaged more easily

• Hair may become frizzy, dry, and prone to breakage

• Color can shift more quickly, resulting in brassiness or orange hues

In 2014, researchers measured the pH of 96 consumer shampoos, finding that over 65% had a pH greater than 5.5, with some as high as 9. Most salon products used after chemical services are intentionally acidic to help lock in color and restore hair's natural pH balance.

Now that we’ve explored how pH affects hair structure, let’s look at the common factors that can disrupt hair's natural pH balance.

when does hair pH change?

Several daily factors can challenge hair's pH balance, including:

• Products and treatments: Every hair care product that contains water has its own pH level, which can either align or disrupt hair's natural balance. For example, many shampoos have a higher pH that causes the cuticle to swell and increases friction between hair fibers. Chemical services intentionally alter hair's pH to open the cuticle or modify the bonds that hold it together, making chemical processes like lightener or relaxers more effective at achieving a particular look–often at the expense of hair protein’s health and structure.
  
  

• Water quality: The water you use to wash your hair may also impact its pH. Tap water typically ranges from pH 6.5 to 9.5, which is above the optimal range for hair, meaning each wash may expose hair to alkaline pH, potentially disrupting its balance.
  
  

• Environmental factors: Daily exposure to sunlight, pollution, and other elements can further disturb hair’s pH balance.

K18REPAIR™ = the pH-optimized salon solution

At K18, we carefully formulate our products with specific pH levels to align with hair's natural chemistry. A prime example is the salon-exclusive K18REPAIR™ treatment, which requires steps in a precise sequence to maintain hair health and optimal pH levels.

Here’s how it works:

1. K18 Professional Mist (pH 7.5-8.0)
   The ideal first step before chemical services like coloring and bleaching, this slightly alkaline mist opens the cuticle, preparing hair for repair and strengthening. 
   
   

2. K18 Leave-In Molecular Repair Hair Pro Mask (pH 5.0-6.0)
   Formulated to match the hair’s natural baseline pH range, this mask helps minimize the swelling of the cuticle while delivering repair and sealing in the K18PEPTIDE™ to restore hair’s strength and elasticity from within.

pH-conscious hair at home

Helping clients understand and manage their hair's pH at home can transform the health of their hair–making for better, deeper, lasting salon results. Encourage them to keep hair in its ideal state between visits by reaching for K18’s pH optimized formulas, like this bestselling, color-protective shampoo which helps reduce excess swelling of the cuticle, preserve color, and enhance shine with every wash.

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