Why does your hair go grey when you get older?

The gradual greying or whitening of hair is a common sign of ageing. It is caused by a reduction in melanin production in the hair follicles. Melanin is the pigment that gives hair its colour. As you age, the melanocytes (the cells that produce melanin) in your hair follicles become less active and eventually stop producing melanin altogether. This results in the loss of colour in your hair, and it begins to turn grey or white.

Several factors contribute to the greying of hair, including genetics, hormonal changes, autoimmune conditions, smoking, stress, and certain medical conditions. Genetics play a significant role in determining when and to what extent a person's hair will turn grey. If your parents or grandparents went grey prematurely, you are more likely to experience it yourself.

Hormonal changes, particularly the decrease in the production of melanin-stimulating hormones, can also contribute to greying hair. This is often observed during pregnancy and menopause. Additionally, autoimmune conditions, such as alopecia areata and vitiligo, can affect the melanocytes and lead to premature greying.

Environmental factors, such as smoking and excessive stress, can also accelerate the greying process. Smoking produces free radicals that can damage the melanocytes, leading to a loss of pigment. Chronic stress can disrupt the normal functioning of the body, including the hair follicles, and contribute to greying.

Certain medical conditions, including thyroid problems, vitamin B12 deficiency, and pernicious anemia, can also be associated with premature greying of hair. If you experience sudden or rapid greying, it is essential to consult a doctor to rule out any underlying medical conditions.