My body and scalp hair are entirely black. Until recently, I thought this was the case with my facial hair also, until I noticed a small handful of hairs that were anywhere from light brown to copper-orange to burgundy-red. There are hairs that are entirely pigmented like this and there are mixed along their length between different pigmentation colors (for example there are copper hairs that have black tips).
Can anyone explain why this is?
My own thoughts are that it is caused by some variation between individual hair follicles (different type/number of receptors on the melanocytes that color hair that cause them to respond differently to various amounts of hormones? But then what is causing the hormone shift in the first place? I am pretty sure that until recently all the hairs were black and only recently have these lightly pigmented hairs sprouted)