Accurate evaluation of skin barrier function is critical for cosmetic product development. Nevisense, powered by Electrical Impedance Spectroscopy (EIS), enables non-invasive measurement of structural and functional skin changes beyond what traditional methods such as transepidermal water loss (TEWL) can detect. Originally developed in collaboration with the Karolinska Institute, Nevisense is clinically validated and has an established medical indication for the detection of skin cancer, including melanoma, supported by FDA approval and CE marking. Using multi-frequency signals that capture over 700 data points per measurement and penetrate up to 2.5 mm, EIS quantifies subclinical barrier alterations linked to hydration, lipid organization, cellular integrity and inflammation. Clinical studies demonstrate that EIS detects early barrier disruption, measures treatment response, and remains robust against environmental and behavioral confounders. Increasingly applied within cosmetic testing, EIS offers a sensitive, reproducible and objective method to assess product efficacy and monitor skin barrier health over time.