Graying of hair is unfortunately one of the consequences of hair aging. While there is no set age for graying, by 50 years old about 50% of most people would have at least 50% of gray hair.
What is gray hair?
Graying is basically the loss of pigment in the hair shaft. In other words, there is little to no melanin in the hair thereby giving it a silvery/ gray look. Gray hair is usually thinner than pigmented hair but also feels more rough and dry because the production of sebum is also lower with graying hair.
What are the causes of hair graying?
- Genetics is one major factor that is out of our control. For that reason, one can even find young people with 50% of gray hair.
- Autoimmune disorders such as pernicious anemia, autoimmune thyroid disease or certain rare syndromes like the Werner syndrome are all reasons why the hair can start to gray.
- Improper diet such as lack of vitamin B was said to cause grey hair but is reversible after treatment.
Contrary to popular belief stress is not the reason for graying but it can accelerate the graying process specially in those who are genetically predisposed.
Why does hair become gray?
Hair’s natural color is due to the melanocytes that are present in the hair follicles and produce the melanin pigment. Melanin itself consists of eumelanin (responsible for brown and black ) and the less prevalent phoemelanin (responsible for yellow and red).
Keratinocytes are cells responsible for building the keratin structure of hair in the anagen stage. During that process, the melanocytes transfer melanin (in the form of small packets of melanosomes) into the keratin fiber. It is believed that graying occurs when there is a reduction of active melanocytes in the hair bulb or due to a disruption during the transfer of melanin into the keratin.
The biochemical controls of the graying process are still not completely understood.