Biochemistry / General / Genetics / Science

Why does hair turn gray?

Gray hair man

Hair- thread like strands that mainly adorne our heads like a crown is a body image enhancer across cultures and societies. It is estimated that we will globally spend USD 211.1 billion by 2025 on hair care products, which just goes to show how much we are in love with our hair and take beautifying it so seriously. Hair is a product of evolution to protect animals from cold in cooler weather and for insulating in warmer weathers and this is a characteristic feature of mammals. It is made of keratin, which is a type of protein which is also found in nails. Apart from this, hair also has other components which provides structure such as sebaceous gland to which the follicle is attached and arrector pili muscle. 

Anatomy of Hair

The color of the hair is determined by the amount of pigment called melanin. This pigment exists in 3 main types in humans namely., eumelanin (responsible for brown or black hair color), pheomelanin (responsible for yellowish/reddish colors) and neuromelanin.  Many genes have been found to be responsible for producing melanin, amongst these MC1R is the best studied gene. Irrespective which hair color one is born with or has in their adult years, almost everyone will have gray hair in old age. Even though the exact reason for this is not very clear, it is widely believed that as we age the cells making melanin die, hence with no supply of melanin, the hair turns gray.  Premature graying also is due to shortage in melanin supply, however this is not age related but is a result of stress and environmental factors. Genes also play a very important role in determining when an individual’s hair turns gray. Certain health problems such as lack of vitamin B12, rare inherited tumors, thyroid disease, vitiligo are also known contributors of gray hair. Smoking is also shown to be one of the factors for graying of hair. Gray hair also feels texturing different from normal hair and this is due to decreased cuticle which makes them dry, fragile and coarse. 

Silverback gorilla

It turns out that even animals have gray hair however the reason is not because they have become old and frail. Male gorillas all have black hair at the back till they are about 12 years old, after this the hair turns gray giving them the name silverback and one such silverback becomes the leader of the group.While animals such as chimpanzees and dogs’ hair turn gray with age just like us.

Chimpanzee with gray beard

Whatever might be the reason, if you gray prematurely or when you are older, don’t fret as you can either embrace it or just color it 🙂

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