Abstract: The present invention is a nail hydration device in which a substrate sheet or film, suitable for application to the fingernail or toenail surface, includes a moisturizing constituent for hydrating the nail material. Preferably, the film is a polymeric film, more preferably a moisture vapor permeable polymeric film, adjacent to which is incorporated an aqueous phospholipid composition, an adhesive layer, and optional hydrolyzed animal protein (gelatin, collagen, etc.). The most preferred aqueous phospholipid composition contains water and soya phospholipids such as, for example, an aqueous soya lecithin emulsion. Typically, the aqueous phospholipid composition is dispersed within the adhesive layer. The films or tapes, which may be backed with a release liner and/or precut in the appropriate shapes, are applied to the exposed fingernails or toenails to hydrate and otherwise treat the nail material to prevent nail brittleness. The films or tapes may be applied periodically on a nightly (i.e.