How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

but I'll find a lone grey hair just as long as the rest of my hair, as if it turned grey overnight. I've never found a short grey hair, just long ones. And as a bonus, why are they so coarse?

How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

Hair color is caused by a pigment (melanin) produced by hair follicles. With aging, the follicle produces less melanin.

Graying often begins in the 30s, although this varies widely. Graying usually begins at the temples and extends to the top of the scalp. Hair becomes progressively lighter, eventually turning white.

Many people have some gray scalp hair by the time they are in their 40s. Body and facial hair also turn gray, but usually later than scalp hair. The hair in the armpit, chest, and pubic area may gray less or not at all.

Graying is genetically determined. Gray hair tends to occur earlier in Caucasians and later in Asian races. Nutritional supplements, vitamins, and other products will not stop or decrease the rate of graying.

How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

hair pegmentation

How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

Stress can do it and also a bad hit in the head.

How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

Children....?

How does a strand of hair turn grey overnight? I could understand if it started out grey and grew..?

"If a strand starts brown, it should fall out brown. ". Actually, this wouldn't be true. Hair is built from the bottom like a sausage coming out of a sausage machine, or icing coming out of a icing bag. So when the melanocytes (there's a name for everything isn't there) stop producing pigment and the hair continues to grow, you would get a hair with a brown end and a gray base.

I also wouldn't be surprised if the pigment tends to be distributed in the outer layer of the hair longer than the inner layers.

This would leave you with a hair that is brown fading to gray, and in the fading zone, the pigment is being worn off daily. When the gray area is close to the scalp it wouldn't be that noticeable. But when it grew out longer it would be more noticeable because the gray stretch would be getting longer faster than the actual hair is. Finally, when there is enough of the gray part, it will lift up above the rest of the hair (because as you noted it is coarser); at which point, whatever is left of the brown part will not be as visible as the gray part.

This is mostly conjecture, I don't have anything to back this up except logic. And I'm blonde, which has its own peculiarities.

Your father is easier to explain. Gray hair (in another example of God's twisted sense of humor) is far less likely to fall out during stress than pigmented hair. So - hair with more pepper than salt + stress = hair with lots more salt in relation to pepper. Check the link below.