Thick or Thin?
For a single hair fiber to be deemed thick or thin depends on its diameter (the width of a circular or cylindrical object). Human hair diameter ranges from 15 microns (very thin) to 170 microns (extremely thick), with the average diameter of scalp hair being between 60 and 110 microns. Of course it’s possible to have a lot of very fine hair on one’s head, but the true determination of whether hair has a thick hair structure or a fine hair structure is its diameter - not the amount of it. The diameter of your hair has a significant impact on how you can style your hair. The thicker a hair is, for example, the more likely it is to be rigid and frizz prone. Conversely, fine hair structures tend to be straighter, far more flexible, and struggle to hold onto a created style.