HOW DOES HAIR GROW?
Scalp hair can grow at a rate of between 0.6 cm and 3.6 cm per month. The growth of human hair depends on the continued keratinisation of epidermal cells. Keratinisation is when a living keratin cell dehydrates and becomes a hardened keratin cell. This process means cells previously growing and dividing below scalp level can turn into the tough and waterproof material that can be continually regenerated and make up the hair strand. The keratin that makes up the hair fibre is produced from cells from the base of the dermal papillae. The bound collection of dead cells that continues to be pushed up the hair follicle ends in the formation of hair seen above the scalp level.
Hair is made up of a protein called keratin and follows a specific growth cycle of three distinct phases: anagen, catagen and telogen. The amount of keratin and the length of the growth cycles determine the length of the hair, the thickness of the hair strand and the rate of hair growth.
WHAT DETERMINES HAIR THICKNESS AND LENGTH?
The hair fibre's thickness depends on how large a keratin cell can grow before it dies and hardens. The hair fibre length depends on how often the keratin cells continue to differentiate into keratin cells without cell inhibition or multiple replication errors.
Blood comprises vital elements for hair growth, such as hormones, irons, amino acids, glucose, and oxygen. The level of diffusion of these vital elements from blood vessels to hair follicles is another determinant of how fast or how thick hair will grow. Other factors influencing hair length include keratin gene expression and transcription success in the keratin stem cells, local androgens, growth factors and inflammation responses. Hair will continue to grow whilst it has the right hair growth signals, keratin gene activity and nutrient supply.
THE FINAL WORD
Keratinisation is complete when the keratin cells are pushed to the scalp's surface to form the visible hair strand. The external hair is completely dead and composed entirely of keratin. The quality, thickness and length of your hair will depend on the early stages of keratinisation (the bit you cannot see).
