We show a novel drug delivery system (DDS)NANOEGG(R) for improved photo-damaged skin therapy of all-trans retinoic acid (atRA) with an egg-like structure in nano-scale.Both irritative symptoms and physicochemical instability of the atRA were improved.The NANOEGG(R) particles developmentally improved the permeability to the stratum corneum, as a consequent the remarkable pharmacological effects were shown as such as follows;1) thicker epidermis than classical atRA treatment, and 2) the overexpression of mRNA for heparin-binding epidermal growth factor like growth factor (HB-EGF) as the provocation epidermal hyperplasia.Furthermore, we found a surprising boost in production of hyaluronan (HA) among the intercellular spaces of the basal and spinous cell layers in epideremis.