corneometer

A corneometer is a non-invasive diagnostic instrument used to measure the hydration level of the stratum corneum, the outermost layer of the skin. It operates by assessing the electrical capacitance of the skin surface, which correlates with the water content within the corneocytes. The device uses a probe that forms a capacitor with the skin; higher water content yields a higher dielectric constant and thus higher capacitance. Readouts are typically reported in arbitrary units, reflecting relative hydration rather than an absolute water concentration.

Corneometers are widely employed in cosmetics and dermatology research to evaluate skin hydration and the effectiveness of moisturizers, serums, and barrier-repair formulations. They are often used in clinical studies, product development, and quality control, and are commonly paired with other measurements of skin barrier function, such as transepidermal water loss (TEWL).

Operation and considerations: measurements are performed on clean, acclimatized skin, with environmental conditions such as temperature and humidity controlled to reduce variability. Multiple readings at the same site are usually averaged. Readings can be influenced by surface moisture, sweat, sebum, residual lotions, or recent contact with water, so standardized preparation and timing are important. Calibration and device maintenance follow manufacturer guidelines, and different models may have varying output scales.

Origin and usage: the corneometer was developed by Courage+Khazaka Electronic GmbH and has become one of the standard tools for corneometry in dermatological and cosmetic science.