Try a university library, and see if they have collections of hair chemistry articles, so you can begin to know whose work to look at, along the lines of what mjc123: suggested. Once at a large university, I saw a 10 volume collection of articles, just on the chemistry of Black skin (hey, that was their title, not mine.) I was really stunned there was that much to talk about the differences between two races skin, but actually, the aging process is very different. There's reams of science many of us don't even realize exists.