The nails are structures formed by keratinized squamous cells produced by the matrix that grow on the nail bed. The hardness of the nail plate and its adherence to the underlying bed are key properties that make them protection appendices due the presence of different types of keratins. Studies have shown the K10 and K14 attendance throughout the stratified epithelium of the nail unit. In this context, filaggrin has the role of stabilizing the network of intermediate filaments of K6 and K16 with hyperproliferative stages, and promote increased epidermal cohesion. With the purpose of maintain the health of nails and improve its appearance, the cosmeceutical market studies new strengthening and fortifying formulations that may influence the biological function thereof. Based on the above, the present study evaluates the efficacy of nail care cosmetical product (NCCP) through preclinical studies in strengthening/repair activity. Human keratinocytes (HaCat) were incubated with 3 non-cytotoxic concentrations of NCCP for 48 hours for further evaluation of the production of keratins 1, 10, 14, 16, 17 and filaggrin. The in vitro results show that NCCP has a strengthening and repair nail effect by stimulating production of filaggrin and keratins 1, 10, 14, 16 and 17 in human keratinocytes, favoring the nail plate hardness and its adherence to the underlying bed.