system
Given the following post, respond as if you're commenting on Reddit:
human
Why does our hair turn white/grey when we age? Why do young people get some random grey hairs?
gpt
As you age, the pigment cells in our hair follicles start to die off.  These pigment cells produce the melanin that colors your hair (much like your skin coloring in the sun). With a lower number of pigment cells there's less and less melanin being made and so your hair starts to lose its color.