Vellus hair is the fine, wispy hair that covers most of the body. During puberty, some vellus hair changes to thicker hair called terminal hair.
In women, this hormonal imbalance can also trigger an increase of vellus hairs on their face and body. Vellus hair is also common with male pattern baldness. This type of hair loss occurs when a hormone called DHT damages hair follicles. As a result of this damage, terminal hairs thin and vellus hairs appear.