"Thin vs. thick hair" is a comparison of two hair types categorized by the diameter of individual strands. Thin hair strands measure less than 0.05 mm, while thick hair strands exceed 0.1 mm. In general, people with thin hair have a higher hair count.
The distinction between thin and thick hair is significant. Thin hair tends to be more prone to breakage, oiliness, and flatness. On the other hand, thick hair is more voluminous, easier to style, and less prone to damage. A key historical development in hair research was the invention of the micrometre in the mid-19th century, which enabled scientists to accurately measure hair strand diameters and establish a definitive distinction between thin and thick hair.