There are many reasons for the increase of gray hair on the head: first, it can be considered the increase of age, with the increase of age the melanin in the hair follicles gradually missing out, so that the gray hair increases. Secondly, excessive mental stress or anxiety or depression can be considered, which may also reduce melanin synthesis in the hair follicles, leading to an increase in gray hair. In addition, some people may suffer from other systemic diseases, such as vitiligo, can also lead to scalp skin whitening, and at the same time involve the hair follicles, so that the melanin within the hair follicles is reduced, causing an increase in gray hair. If there are any of the above causes of gray hair increase can be targeted treatment to prevent further spread and spread of the disease.