Why does hair turn grey?

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Some people dread it. Some embrace it. Whatever be the reaction people have to salt-and-pepper hair, greying hair is an inevitable aspect of life. People reminisce on their days of youth by admiring their head full of brown (or blonde or red) hair, which now appears silver and thinner. While it is still popular practice to use HAIRDYES or HENNA (commonly called Mehendi) to ‘restore’ the color of the hair, these solutions and temporary and wear out after a few washes.

Biologically, a head full of hair (for women and men) is a sign of the youth and fertility of an individual. However, this biological perspective has now taken on a societal norm, which encouraged people of all ages to ‘cover their greys’ to appear younger than their actual age. Yet, the last decade has seen a shift in the mentality, that people choose to style their grey hair and adopt the sign of aging with an open mind.

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How does hair turn grey?

Contrary to popular belief, hair does not ‘turn’ grey. A strand of hair has two parts – the SHAFT and the ROOT. The root of the hair is inside the EPIDERMIS, from where the hair stand originates. It then grows through the HAIR FOLLICLES on the uppermost layer of the skin and the portion protruding (which we can see) is called the shaft.

The hair grows from the root, i.e., the newer hair cells are aggregated at the bottom of the hair strands. The understanding of so is necessary since the shaft is pushed out of the follicles only when the root produces a strand long enough to do so. Understanding the mechanism can help one realize that the hair that we see as brown cannot change its color to grey.

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The root of the hair is associated with a PIGMENT. The pigment of these cells is called MELANIN, produced in the MELANOCYTES. Melanin is the pigment present in our skin which determines the complexion of the skin. If the production of melanin is low, the skin will appear paler and if higher, the skin will be darker. The production of melanin (for the skin as well as hair) is determined by the genes present in the individual. Thus, there are different skin tones and hair colours.

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When younger, the shaft of the hair strand grows to its average length in the original colour. After its life cycle completes, it falls out. However, as the age progresses, the melanin-producing cells are blocked and hence, the hair which grows from the roots adopt a ‘TRANSLUCENT’ colour – which is usually visible as silver or grey. Thus, the occasional grey hair that is noticed is a new strand of hair and not a colour change of the hair strand with melanin.

Why does hair turn grey?

As mentioned before, the melanin production of the body cells depends on the genes passed on from the parents. It is also observed that the age at which most people notice grey hair is around the time their parents first observed grey hair on their head. A study claims that a person is at risk of having grey hair at the age of 35. However, there is also a concept called the 50-50-50 THEORY. The 50-50-50 theory claims that half of the population will notice 50% of their hair turning grey at the age of 50. While this theory is based on an average, an individual may have a different experience, depending on their genetics.

Anyone who has dyed their hair a different colour (such as red or blonde) must have noticed their hairdresser BLEACH their hair before applying the dye of the desired shade. BLEACHING is a process that is used in nearly all industries – such as clothing, paints, cosmetics – to lighten a substance by exposing it to a bleaching agent. Bleaching agents may be chlorine or oxygen, which trigger a chemical process in the respective substance and lighten its appearance.

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The bleaching agent used to lighten hair contains HYDROGEN PEROXIDE. Hydrogen peroxide (H2O2) is a weak acid, which imparts no damage to the hair while bleaching it. The chemical, when applied to the hair, tends to degrade some of the melanin and prepare the hair to accept another colour. This technique is most popularly used to dye naturally brown hair.

It is a little-known fact that the chemical hydrogen peroxide is often generated as a BYPRODUCT at the roots of the hair. When the cells at their prime (usually during youth), hydrogen peroxide is broken down. However, as a person ages, their cells are unable to breakdown the chemical produced. As a result of this, melanin production is blocked and the resultant hair strands are ‘bleached’, looking grey.

Which factors lead to greying of hair?

  1. Genetics

Since the rate of melanin production is inherited from the parents, genetics plays a crucial role in determining when a person will grow their first grey hair.

  1. Stress

Stress has not been conclusively labelled as the leading cause of greying of hair. However, stress does cause hair fall and can reduce the number of natural hair strands, making the grey hair more noticeable.

  1. Ethnicity

Caucasians are likely to observe grey hair earlier than Asians or Africans. It is true people with naturally blonde hair will notice greying sooner since they already possess less melanin. However, the reason why Caucasians with naturally brown hair have early onset greying is up for discussion. Asians are next in line and the most delayed greying is observed in Africans.

  1. Vitamin deficiency

People with a deficiency of vitamin B12 (CYANOCOBALAMINE) are observed to be at a higher risk of growing grey hair at an earlier age.

Ageing is a process as natural as the start of life. The cycle of life has various stages and each stage brings newer situations and in fact, appearances. One cannot expect to have their natural hair colour all their life, just like one cannot expect to have youthful skin forever. Each grey hair and wrinkle represents the triumph of life over the hardships of the world. Whether people choose to embrace the greyness or to cover it up, it is nothing to be ashamed of.

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