In the present study, and for the first time, we have checked the possibility of obtaining a partial demineralization of seawater (raw water from Biarritz, France) using the denoted NF90 membrane (Dow, USA), for the preparation of personal body washing solutions (salinity near 9 g/L). The operation occurred in two successive NF stages. Then the possibility of NF reducing both the overall salinity of natural salty waters such as seawater leads the way to potential applications in the field of human health (e.g., preparation of nasal sprays, medical dietetics, hot mineral springs).