Hair Chemistry 101

Before you get into coloring hair, it’s useful to understand the structure & chemistry of hair.

Basics of Hair:

The hair shaft is composed of three major parts: the cortex, medulla, & cuticle.

Cortex:  Contains melanin and moisture.

Melanin is what determines hair color.
There are two main pigments:

- Eumelanin- black & brown pigments  
- Pheomelanin- red & yellow pigments that give your hair warm tones

Medulla: Innermost layer of hair shaft.

Cuticle: Protective, outer layer of hair shaft.  Made up of little scales that lay flat or are raised.

Smooth vs Raised Cuticle:

  - Smooth/closed cuticles result in healthy hair since moisture and
  shine is locked in. 

  - Raised cuticles results from the use of chemical products.
  Hot temperatures will also raise the hair cuticle.

pH of hair: 

  Healthy hair will have a pH between 4 and 5.5.
  Acidic products will promote closed cuticles while
  Alkaline products will promote open cuticles.

Hair porosity is the ability of your hair to absorb moisture.

You can perform a simple test to determine the porosity of your hair.  All you have to do is drop a clean hair strand into a glass of water and see where the strand is after a couple of minutes.