What cause hair color?

The color of a person's hair is primarily determined by the amount and type of melanin present in the hair follicles. Melanin is a pigment that gives color to the skin, hair, and eyes. There are two main types of melanin: eumelanin and pheomelanin. Eumelanin is responsible for brown and black hair colors, while pheomelanin is responsible for red hair colors.

The amount and type of melanin in the hair follicles is determined by genetics. Genes control the production of melanin-stimulating hormone (MSH), which in turn stimulates the production of melanin. The more MSH that is produced, the darker the hair color will be.

In addition to genetics, other factors can also affect hair color, such as age, diet, and exposure to sunlight. As people age, the production of MSH decreases, which can lead to gray hair. Diet can also affect hair color, as certain foods can contain nutrients that help to promote healthy hair growth and pigmentation. Exposure to sunlight can also lighten hair color, as the UV rays in sunlight can break down the melanin in the hair follicles.