Back to Basics: How Natural Hair Colour is Formed

Hair at the root is alive and needs to be treated with care and respect; when using chemicals to change the colour properties of hair, it is important to know how and why these changes occur.


The more knowledgeable you are, the more a client will trust you and listen to your advice.


Natural Pigments in Hair Melanin

Natural hair colour is produced from tiny pigment granules – melanin – found within the fibrous cortex layer of the hair. Light penetrates the clear cuticle scales, some of which is reflected back to the eye. The colour we perceive depends on what light is reflected back; the type, quantity and mix of the two pigments found within natural hair determine this.


A cell type, called a melanocyte, is responsible for the production of melanin within the root bulb of the hair. The catalyst tyrosine, found within melanocytic cells, is responsible for triggering a chemical reaction resulting in the formation of melanin. This is where two distinct melanins are created: the brown-to-black eumelanin and the yellow-to-reddish pheomelanin.


The combination of eumelanin and pheomelanin create the natural colour in hair, and the concentration determines the colour depth.


Depth and Tone

A description of colour depth and tone can help define and describe different colour types. Colour depth is influenced by the quantity of melanins found within the hair: more melanins create darker hair and fewer pigments create lighter hair.


The pigment, eumelanin, is the more dominant of the two due to its brown to black colour. Colour depth can be divided into ten levels, from black through to light blonde, however within each depth of colour there are several shades or tones. This relates back to the colour wheel, for example light blonde can have a golden, matt or cendre (ash) hue.


Pheomelanin is mainly responsible for the underlying tones found within hair. When going lighter in colour, certain natural tones called undertones will be apparent. These are important to identify when analysing hair colour during a consultation, as the primary undertone will influence final hair colour. In certain cases these may need to be bleached, or counteracted with an opposing tone from the colour wheel, in order to achieve a target colour.


An international level system is used to measure colour depth:

  • Levels 1 to 4 – red is the primary undertone
  • Levels 4 to 5 – red/orange is the primary undertone
  • Levels 5 and 6 – orange/red is the primary undertone
  • Levels 7 and 8 – orange/yellow is the primary undertone
  • Levels 9 and 10 – yellow is the primary undertone