When I dry my hair I noticed that the many, many grey hairs dry much faster than the rapidly dwindling darker ones.
Anyone know why?
As you can tell I have too much time on my hands. 
@kopenhagen5 wrote:To hazard a guess, the grey also curl more rather than stay straight, sticking to together retaining moisture.
I also think the grey are dryer naturally.
Sorry to be of very little help here.
I go to have the grey put in - in order to look my age.
They say that Grey hair is inherited.............................................................................. You inherit them from your children 
