The hair’s pigmentation:
It has been found that individuals with different hair colours experience hair loss at a different rate due to the amount of hair strands they have. Pigmentation in the hair is produced by specialised cells, or melanocytes, which manufacture the melanin pigment within the hair itself. These cells are located within the hair follicle and dictate the pigmentation of the hair strand from the root. Melanocytes are not only found at the root of the hair strand, but throughout the body. Eyes, ears, the nervous system, skin and mucous membranes all contain these specialised pigmentation cells.
Only active during the growth cycle of the hair, melanocytes ensure that hair is only pigmented when the hair is in the anagen phase. The catagen (degradation) or telogen (resting) phases of the hair cycle do not need melanin to be created or synthesised. White hair does not contain any melanin pigmentation.
There are two main types of melanin synthesised by melanocytes within the hair follicle, but only one form is created at any given time.
- Eumelanin: the black or brown pigment in the hair is created by oval melanocytes.
- Pheonmelanin: a yellow or reddish-brown pigment created by spherical melanocytes.
The structural proteins in the cortex at the centre of the hair shaft (the keratins) absorb this melanin pigmentation, the production of which is regulated by a genetically programmed enzyme and other molecules unique to each person. This explains the difference between ethnic hair types and individual hair colouring. The shades of pigmentation in the hair itself are caused by the amount of eumelanin or pheomelanin which is absorbed by the protein within the hair shaft. This shading creates hair which, for instance, could be platinum blonde or strawberry blonde, dark brown or light brown.
Subtle changes in the shades and the way in which we see pigmentation in hair can be caused by two things. Firstly, the reflection and refraction of light from external sources onto the hair shafts can cause changes in the hue. Secondly, the sheen created by certain hair styling products can cause alterations in the hair volume and pigmentation due to the reflection and refraction of external light sources.
Although the colour of a person’s hair does not directly determine their hair volume and hair loss susceptibility, it is however linked to the amount of hair strands they have on their scalp. There are between 90 000 and 150 000 of individual hairs on the scalp. Roughly 100 hairs are lost daily by brushing and washing one’s hair, as well as general living conditions. More hairs can be lost if the person’s hair is long, dry or unhealthy. Blonde individuals have the most scalp hairs, accounting for the thickest hair volume, at over 140 000 hairs. Brown / brunette individuals have between 120 000 and 140 000 scalp hairs, while those with black hair usually have between 100 000 and 120 000 scalp hairs. Red heads usually have about 90 000 individual hairs.
Voluminous hair is defined as hair which maintains its body and fullness. Hair volume is degraded through continuous and extensive hair loss. The volume of the hair enables the hair shafts to be held away from the head, creating an attractive look.
The volume of the hair is determined by the thickness of each hair strand, or the diameter of the hair itself. Additional prerequisites to hair fullness include:
- Hair density (hair strands on the scalp per square centimetre)
- Stiffness of the hair
- Curl in the hair strands (curly or wavy hair has more density per strand than straight hair).
- The stickiness of the hair, or how much the hair strands attract one another.
Hair volume, colour and count are generally determined by physiological factors and are genetically inherited. If a person’s immediate family has thick, brown hair, the chances are good that that person will have thick, brown hair. Although genetic abnormalities and lifestyle changes affect hair loss, treatment is symptomatic and specialised on a case to case basis.