The growing hair resists pulling out of the skin in particular site, where the keratinization of hair cortex and hair cuticle cells as well as the cells of the hair inner root sheath (IS) (being in tight contact) are advanced enough to make them rather strong but lower the level where the hair separates from the hair inner root sheath. The hair which does not grow is kept for some time within the skin by the direct contact of the keratinized hair cortex cells with the cells of the hair outer root sheath. Such contact is absent at the phase of growing hair and even in the case of proliferation inhibition in the follicle bulb causing the lack of hair resistance to pulling it out of the skin several days after inhibition induction.