The pH of the hair

What is pH in hair?

We often hear about the pH of hair and cosmetic products. 

The pH is the potential of hydrogen, and indicates the concentration of hydrogen ions present in solutions. That is, it’s a unit of measurement that determines the alkalinity or acidity of a substance.

The pH scale

The pH scale ranges from 0 to 14, with 7 being a chemically neutral pH. 

Thus, values from 0 to 6 represent an acidic substance, while values from 8 to 14 represent a basic or alkaline substance.

The pH of the hair

Each hair type has a different pH. 

Healthy hair, in an optimal state of health, usually has an acidic pH (between 5 or 5.5), so we can say that hair is naturally acidic. 

Why does the pH of hair become unbalanced?

When the pH of hair is between 5 and 5.5 , the cuticle is closed and smooth, looking healthy and shiny. This is usually hair which has not been chemically treated. 

But when we subject the hair to bleaching or colouring processes, which are very alkaline, the hair tends to alkalinise. This pH imbalance makes our hair look dull and rough. In these cases the cuticle opens more easily, so the hair is weaker and tends to frizz. 

Super TIP

For healthy, pH-balanced hair, choose quality products and avoid subjecting your hair to extreme treatments.