• 1Hair follicles that are in their active growth phase produce hair that grows, gains pigment and thickens.
  • 2Active hair growth ends when hair is cut off from its blood supply and the cells that produce new hair.
  • 3Hair begins to be shed while follicles may enter into a resting phase before new hair growth.
  • 4New hair begins to form from the follicles, beginning the cycle all over again!


1. Paus R. & Cotsarelis G. (1999). The biology of hair follicles. Massachusetts Medical Society. 341(7); 491–497.