Stratum corneum hydration (corneometry)

Method

Electrical capacitance of the stratum corneum measured with a corneometer probe at a defined skin site after a standardised acclimatisation period, in arbitrary corneometer units. Site (cheek, volar forearm, palmar or dorsal hand), ambient temperature and relative humidity recorded on the edge; sites are reported separately and are not pooled.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

CRITICAL SIGN INVERSION against transepidermal water loss, measured in the same sessions with a probe on the same patch of skin and reported under the same heading of 'skin barrier function': hydration improves by RISING and water loss improves by FALLING. They are not measuring the same property either — capacitance reports water content in the outermost layers while transepidermal water loss reports flux across the barrier, and the two can move independently. Also distinct from skin brightness (L*), a colorimetric reading from the same instrument panel and often the same visit.