- Corneometer / Dermal Phase Meter (Humectant Products)
- Tewameter (TEWL – Emollient Products)
- Moisturizing, combats dehydration, moisturizes for up to ‘x’ hours, soothes and softens skin, improves skin’s natural barrier and more.
Briefly, what you can expect:
Corneometer / Dermal Phase Meter Assessment:
- 15 healthy male and female subjects to be assessed for a product’s ability to draw moisture into the epidermis from the atmosphere. Study length varies on moisturization claim but standard test is 24hrs. The positive control is glycerine and the negative control is untreated. Dermal Phase Meter used for US studies or if requested.
- Active Phase: Typical timeline for assessment will be 0 (pre-treatment), 1, 3, 5, 8, 12 and 24 hours during the day (and 48hrs if the claim needs to be as such). Both instruments have a large capacity and are pressed against the skin which measures the hydration of the stratum corneum. They evaluate the Dielectric Constant of the skin as a ratio to water (constant of 1) as differences in hydration will manifest within this measurement. The value produced is an arbitrary Corneometer / Dermal Phase Meter value.
Tewameter (TEWL) Assessments:
- 15 subjects – Product versus no treatment with assessments at t=0h, t=1hr, t=8hrs. This assessment is normally used for emollients – a moisturizer that acts as film over the skin to improve skin barrier functionality between the skin and the exterior environment. We measure the Trans-Epidermal Water Loss – the amount of water lost across the epidermis – which makes it possible to measure the invisible, yet steady evaporation of water through the epidermis.
- Active Phase: The ‘open cylinder’ method consists of two moisture sensors coupled with temperature sensors inside a cylindrical probe that is placed on the skin. It is in this probe that the temperature and the moisture content of the rising water vapor are measured and the TEWL rate is calculated as grams per square meter per hour (g/m2h). Should the barrier function of the skin be impaired in any way, this leads to a dramatic rise in the TEWL value. Study design is similar to humectant products.