At puberty the immature vellus-like hairs on our bodies can change to terminal hairs. This change results from the dramatic rise in androgen levels at that time. It is especially noticeable in young men. Young women who suffer from the condition of anorexia nervosa, however, stop having periods and produce very little oestrogen: their natural androgens tend to thicken their fine vellus-like hairs in the same way.
The effects of androgens continue long after puberty. Some areas of the skin respond to these hormones more vigorously than others do, and at different times of life. Pubic and armpit hair begins to grow at or soon after puberty. Most men's beards do not grow strongly until the owners reach their thirties. The growth of chest hair reaches a peak even later, and hair in the nose and ears grows most in late middle age.
The effects of androgens continue long after puberty. Some areas of the skin respond to these hormones more vigorously than others do, and at different times of life. Pubic and armpit hair begins to grow at or soon after puberty. Most men's beards do not grow strongly until the owners reach their thirties. The growth of chest hair reaches a peak even later, and hair in the nose and ears grows most in late middle age.