vellushår

Vellus hair, or vellushår in Swedish, is a type of fine, short hair that covers much of the human body. It is usually pale and barely visible, with a small diameter and low pigmentation compared with terminal hair. Vellus hair grows from hair follicles that are often associated with sebaceous glands, and its growth cycle is shorter than that of terminal hair.

Distribution and appearance: In adults, vellus hair covers most of the skin, including the limbs and trunk. It is typically absent on highly glabrous areas such as the lips, palms, and soles, and its presence on other regions, including parts of the face, varies with genetics and hormonal influences.

Development and transformation: At birth, most skin areas carry vellus hair. During puberty, androgens promote the transformation of many vellus hairs into thicker, longer terminal hairs in certain regions—such as the underarms and pubic area, and on the face in men. In women, terminal hair tends to be less extensive, so a greater proportion of skin may retain vellus hair.

Function and clinical relevance: Vellus hair provides limited insulation and sensation compared with terminal hair. The balance between vellus and terminal hair is influenced by hormones and age. In some conditions, the proportion changes: androgen excess can increase terminal hair in androgen-sensitive areas, while conditions like androgenetic alopecia can cause scalp terminal hairs to miniaturize into vellus hairs. Vellus hair can also reflect hormonal status or aging in certain contexts.

Related topics include hirsutism, terminal hair, and alopecia.