What determines the size/diameter of a hair strand?

The size or diameter of a hair strand is primarily determined by the size of the hair follicle. The hair follicle is the structure in the skin from which the hair grows, and its size plays a crucial role in the thickness of the hair. A larger follicle can produce a thicker strand, while a smaller follicle typically yields finer hair.

The other factors, such as the color of hair, the health of hair, and the type of hair product used, do not influence the fundamental size or diameter of the hair strand itself. Hair color is related to the type and amount of melanin present and does not affect diameter. The health of hair can influence its integrity and shine but does not change its size. Similarly, hair products may affect the appearance and texture of the hair temporarily but do not alter the actual structural diameter of each strand. Understanding these distinctions is essential in cosmetology, especially when considering hair care and styling techniques.