Hair follicles that exist on much of the human body (including some females) which respond to androgens (primarily testosterone and its derivatives).

Generally, the rate of hair growth increases and the thickness of the hairs increases in direct proportion to the androgen levels; however, different areas respond with different sensitivities.

As puberty progresses, the sequence of appearance of sexual (androgenic) hair reflects the gradations of androgen sensitivity. The pubic area is most sensitive, and heavier hair usually grows there first in response to androgens.