Hair is made of keratin, a tough protein, and grows at different rates in different people. Hair is anchored into the skin via a hair follicle, the hair follicle is placed on the hair bulb, and in the hair bulb living cells divide and grow to build the hair shaft.
Hair colour is caused due to pigmentation. Pigment-producing melanocytes produce melanin in the hair follicle as our hair grows, resulting in our hair colour being formed as well as increasing hair length. On average, the rate of hair growth is around one centimetre per month. However, as our cells start to become damaged during our lifetime, the melanocytes stop working efficiently and become lost. When all the melanocytes are lost in a particular hair follicle, the next hair that grows will be gray or white.
There are two main hair colour pigment types – eumelanin and pheomelanin. Eumelanin produces black and brown colours whereas pheomelanin produces orange and yellow colours. Our genes determine a specific mixture of these pigments to each individual, giving each of us our unique hair colour (although hair colour tends to be similar within families). The exact mechanisms that control pigmentation have not been found out yet, however it is believed to be linked to highly efficient communication between cells in the hair follicle.
Hair progenitor cells release a protein called stem cell factor which enables the production of pigment of pigment. If this protein is absent, hair colour will be lost. In addition, when hair growth stops melanocytes naturally die and when a new set of melanocytes are produced in the next hair growth cycle, the hair produced either lacks colour or looks grey/white. The hair follicles of uncoloured hair have absent melanocytes and excess cellular damage.
So, in a nutshell, ageing causes pigment cells to die, causing out hair to turn grey. Now, more importance is being put into research based on why some people start to lose hair colour in their 20’s and others later on in life. Recent research has hinted that variance in the gene interferon regulatory factor 4 could play a significant pat in early greying.
Thank you for reading this weeks blog, I hope you found it interesting!