Why does your hair gray differently depending on location?

I know that —as a consequence of age-- our hair becomes grayer and eventually white. I have read explanations as to the cause and they make sense.

But what is the reason that different parts of our bodily hair grays or whitens at different rates?

In my 30’s I had very dark brown hair on my head, no trace of gray. But my beard became super gray-----almost white. Ditto with my chest hair. Underarm hair and pubics --no trace of gray.

At 62 the hair on top of my head now matches my beard and chest hair-----almost white. Underarm hair and pubes don’t look any different in color than when I was 20.

There must be some sort of reason for all this variation.

Don’t know what people in their 80’s or 90’s look like in covered areas. Do pubes and underarm hair stay always the same color as that of a 20 year old?

Maybe if we could find out the secret--------we could make a fortune in replacing hair dye for something more natural.

Good question - I don’t know the answer.

I am 44 with almost no gray in my head hair, but on the inside of both forearms my hair is almost white. Every other hair on my body is the color it was since I was born, but since my mid 20’s, these little patches have been there. Wierd.

Well this one sure died quickly enough. Maybe my language was a bit of a turn off.

Sorry 'bout that.

But I still think that it is a very interesting question.

If hair goes gray and then white because of normal ageing-------why do some parts of all of our bodily hair seem to age drastically differently than other parts?

And if we could find out why -------then I think we could isolate what causes that and---------TA DA

We could all be like Ronald Reagan.

I’ve heard that the beard often goes gray earlier than hair on your head because the pigment cells don’t activate as early and aren’t geared to last as long, but I don’t know if it’s true. On a personal level, I’m kind of amused by people who go gray like Dennis Miller has - last I saw, his beard was still dark, but the goatee area had gone gray. It’s a pretty distinctive look.

No, I think people just don’t know. It’s a curious thing.

OK —I can go for that. One of those imponderables I suppose. Kind of like the existence of God. Who knows?