The hair in every person?s scalp grows in tiny groups called Follicular Units. Although scientists have recognized this for some time, physicians performing hair restoration surgery largely ignored their existence. The Follicular Unit of the adult human scalp consists of 1-4 terminal (full thickness) hair follicles.

The Follicular Unit is very small and can only be identified under magnification. The instrument commonly used to measure these naturally occurring groups is called a Densitometer. It is a simple tool that is placed on a small area of scalp whose hair has been clipped closed to the skin surface. Its use should be an integral part of your hair loss evaluation. Follicular Units are best viewed under a microscope, where they are seen as well-formed structures in the skin.