THE SCIENCE BEHIND
Coarse hair is 90 to 110 microns in diameter,
is thicker than sewing thread,
and has a rough texture with high volume.
Thick hair covers more of the scalp but is
not densely populated and
absorbs a lot of oil without producing much.
Coarse hair can range from straight (i.e. Asians)
to coily (i.e. Afro-Caribbean),
and is also common for people with red hair.