Abstract: A method for promoting keratinization of the hair, nails, and skin on the body of an animal or human in which a therapeutic amount of a benzimidazole sufficient to cause keratinization is administered either systemically or directly to the site on the body at which keratinization is desired. The method is useful for the treatment of a wide variety of hair loss disorders in humans such as alopecia, is useful for the treatment of hair loss disorders in animals, is useful for enhancing the strength and length of fingernails and toenails in humans, and is useful for enhancing the strength and length of claws, horns, hooves and antlers in animals. The method is also useful for the topical treatment of fungal infections, for skin replacement or grafting, and for wound healing.