Grey hair is when the natural pigment in your hair (melanin) starts to decrease.

This can happen gradually as you age, or it can happen prematurely.

Premature greying happens for many reasons, such as old age, genetics, stress and pregnancy.

There are also some medical conditions that can cause early grey hair; these include anemia and vitiligo.

When someone has graying hair on their head, but not anywhere else on their body, this could mean they have aged prematurely.

There are many possible causes of premature greying, including genetics, stress, smoking and certain medical conditions.

If you notice your hair starts to grey before you turn 30, it's worth talking to your doctor to rule out any underlying health issues.

Prevention measures include: - Avoiding over-styling your hair - Using natural products  - Eating a healthy diet that is rich in vitamins A, C and E  - Minimizing stress levels  - Regularly using sunscreen when exposed to the sun

Try using anti-grey hair products available at most drugstores.

See your doctor for treatments like laser therapy that work by slowing down the production of melanin in the hair follicle.

Use a home remedy of onion juice on your scalp twice a day until the problem clears up.

To make onion juice, chop an onion into small pieces and boil it in water for fifteen minutes.

Remove from heat and let cool before applying. Leave on the scalp for five minutes before rinsing off with warm water.

You should notice improvement within a week or two.

You may also wish to take supplements such as biotin, which strengthens the hair shafts so they don't break as easily.