Structure of the Skin by ischinca November 29, 2019 Human skin is composed of three layers: the epidermis, dermis and hypodermis (subcutaneous fat). Most topical skin products only penetrate the epidermis and have little to no effect on the dermis. In the dermis, a gel-like ground substance (primarily water and hyaluronic acid) supports a lattice of protein fibers (collagen and elastin). Share FacebookTwitterPinterestEmail