Graying of Hair: Why Does it Happen?

The graying of hair happens due to physical and chemical processes that unleash when your hair loses its natural pigment. However, there are several investigations going on and they say the results could lead to the reversal of this process in the near future.
Graying of Hair: Why Does it Happen?

Written by Edith Sánchez

Last update: 27 May, 2022

The graying of hair is inevitable for most human beings. It’s a natural biological process that comes with aging. However, it could also be due to other factors.

Gray hair has much more impact on aesthetics than biology. For this reason, many people panic when they see gray hair in their mane and attempt all sorts of things to hide it. Others dye it before it even appears.

The probability of graying increases by about 10 to 20% throughout each decade of your life after your 30th year of age. However, there are people with gray hair who are younger than 30.

So, what causes this natural process? Keep reading to find out.

Graying of hair

A woman looking at her hair roots.

Gray hair usually appears progressively as we age. However, note that we all have white hair before we’re born, at the beginning of our lives. During the fetal development process, it begins to acquire colors due to melanin, a pigmenting substance.

There are two types of melanin:

  • Eumelanin, which leads to dark hair color.
  • Pheomelanin, which leads to a light hair color.

Both combine at times and give rise to other hair tones such as brown, red, etc. Melanin forms in cells called melanocytes, whose function is to produce the hair pigment. When gray hair comes out, it’s because melanocytes are no longer producing pigment.

This can happen at any age, but it’s very rare when it occurs in people under 20. When it occurs before the age of 30 it’s due to premature graying or canities.

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Why does gray hair occur?

There are some common myths about the reasons why hair turns gray. However, science has only specified two fully proven causes.

  • Genetics: Even though the genes responsible for this process haven’t yet been identified, we know that genetics plays a decisive role. Among other things, it determines the age at which hair begins to lose its pigment and turn gray. Also, there are more cases of premature graying among Caucasians and Asians.
  • Diseases: Conditions such as vitiligo are due to loss of pigment. Also, pernicious anemia, lack of vitamin B 12, hypothyroidism and Werner syndrome have a similar effect.

Some suggest that other factors promote or accelerate the graying process. However, there’s no proof this is the case, although there are indications of its influence. These are:

  • Stress: The alteration of the metabolism and hormones caused by stress could impact the production of melanin. People who go repeatedly go through difficult times tend to gray at a faster speed.
  • An unbalanced diet: Some researchers suggest that the low consumption of antioxidants and mineral vitamins impacts the degree of graying.
  • Toxic substances: Some believe that smoking and alcohol consumption and drug use may lead to gray hair. However, there’s still no solid evidence behind this claim.

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New data

A man relaxing.

A group of German scientists conducted an investigation in which they concluded that the low production of melanin is due to an excessive presence of hydrogen peroxide in the capillary cells. The way to avoid this is to consume foods rich in catalase, such as avocados, leeks, onions, and beef liver, among others.

Likewise, Professor Desmond Tobin, from the University of Bradford in the UK, concluded there’s a kind of biological clock in the hair follicle. This is what determines when the melanocytes stop producing hair pigment. The novelty here is there’s evidence that the graying process is even reversible.

Meanwhile, a study conducted at the University of Cairo, Egypt, led by Professor Irini Samuel, found that there’s a link between the process of graying and coronary risk in men. Gray hair at an early age could be a telling sign of this.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Castaño, C., Lorente, C., Martins-Froment, N., Olivero, E., & Thomas, A. (2014). Degradación de hormona estimulante de melancitos fotosensibilizada por pterina. Investigación Joven, 1(2).
  • Montaudié, H., Bertolotto, C., Ballotti, R., & Passeron, T. (2014). Fisiología del sistema pigmentario. Melanogénesis. EMC – Dermatología.
  • Buendía, Agustín Mazuecos, J. C. F. (2018). Anatomía y fisiología de la piel. Manual de Dermatología.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.