* Individual: People have different hair thicknesses naturally.
* Hair type: Coarse hair is generally thicker than fine hair.
* Age: Hair can become thinner with age.
* Health: Certain medical conditions can affect hair thickness.
On average, the width of a human hair is between 50 and 100 micrometers.
To put that into perspective, a micrometer is one millionth of a meter. So, a human hair is about half the width of a human red blood cell.