What type of hair almost never has a medulla?

Vellus hair is characterized by its fine, soft, and short nature, and it typically lacks a medulla, the innermost layer of the hair shaft. The absence of a medulla in vellus hair is a key distinguishing feature, as this type of hair is primarily found covering much of the body and provides little insulation or protection. Vellus hair plays a role in the overall function of the skin but does not have the same structure or density as terminal hair, which does contain a medulla. This structural difference is important in understanding the varying types of hair on the human body and helps in different styling or treatment approaches in cosmetology.