system
Given the following post, respond as if you're commenting on Reddit:
human
Why does our skin not turn gray with age?

As we get older, the melanin in our hair dies out, and gray hair starts to grow in place of colored hair. Since skin has melanin in it too, why does the same thing not happen?

Edit: Thanks for all the replies, guys!
gpt
Genes that regulate skin pigment are different genes from those that regulate the melanin in one's hair.  Also, it has been suggested that hair follicles have “melanogentic clocks," which slows down or stops melanocyte activity (the things that produce melanin), and therefore decreases the pigment in one's hair. (loc.gov)