With a growth rate of about 1.3 centimeters per month, Asian hair is the fastest-growing hair of any ethnicity. The hair follicles of Asian people are oriented perpendicularly to the scalp, resulting in straight hair.
According to L'Oreal, hair can be divided into three ethnic types: Asian, African and Caucasian. Each type of hair has its own unique characteristics. Asian hair strands, for example, are generally lighter or less dense than other types of hair.
In contrast, African hair, which is typically black, grows the slowest of the three types at 0.9 cm every month. It owes its curly nature to the hair-follicle positioning, which is parallel to the scalp. As a result of the parallel orientation, the hair growing out tends to curl around itself.
The third type of hair is Caucasian hair, which includes the hair of many Americans and most Europeans. Hair for this ethnicity grows about 1.2 cm per month and is the densest of the three. Caucasian follicles are slightly oblique from the scalp, causing the hair to grow in a slightly curved pattern. This commonly results in wavy hair.
While each ethnic hair type can have various subclasses, such as Indonesian or Japanese hair in Asians, the differences between subclasses are minor.