The average diameter of a human adult´s hair is around 70 micras (0.70 mm), being very thick when it is 0.1 mm and very fine when it is 0.025 mm. One important fact is that as a person ages, the diameter of the hair grows smaller; it loses thickness.
When we talk about thickness we are referring to the coarseness of each individual strand of hair, not to the totality of hair on a person´s head.
Thickness, as well as the type of hair, are important characteristics to be aware of because both affect the ability to grow long hair. For example, coarse hair has the largest circumference, making it the strongest of all hair textures. This makes it easier to grow long because it is more resistant to damage.
To discover your hair type, you have to take a strand of hair (from a comb or brush) and hold it to the light:
- Coarse hair: Thick strands whose shed strands usually are easily identified against most backgrounds;
- Medium: Strands that are neither coarse nor fine; medium hair feels like a cotton thread. You can feel it, but it isn´t stiff or rough.
- Fine hair: Thin strands that sometimes are almost translucent when held up to the light.
Gene or region studied