Curious why your skin has that tone or your hair is that color? Melanin is why.
Melanin is the natural brown hued substance that causes skin pigment and hair color, as well as your eye color. It is produced by melanocytes, which are specialized cells in your skin and hair follicle. Everyone roughly has the same amount of these cells, but what causes your skin pigment and hair color difference is how much melanin they produce.
Besides causing skin pigmentation and hair color, melanin absorbs ultraviolet light to protect your skin from sunburn and sun damage.Sunlight stimulates the generation of melanin, which is why you tan orfreckle.
Two other skin conditions that involve melanin are ablinism and vitiligo. Albinism is caused by a genetic disorder for which various substances that are needed to make melanin are not available. Whereas, vitiligo is caused by a problem with the melanocytes, so no melanin can be rendered. In both cases, the lack of melanin results in the absence of skin pigment.
Melanin also is the reason you hair turns grey as you get older. Hair color transition to gray is caused by melanocyte activity slowdown or stoppage, which in turn reduces the amount of melanin in your hair. And because this reduction occurs at different rates in different hair follicles, a change in hair color to grey can occur rapidly or slowly over time.
You hair color can also change to lighter or darker shades of brown throughout your life. These hair color changes are believe to be caused by stuff like:
And the reason your hair lightens up in color from the sun is because it destroys melanin. And the reason skin pigment doesn’t do the same is because your skin is alive, so it can replace lost melanin. Hair is dead, so no mechanism for regaining its color.