The skin is the largest organ of the human body. It provides several defensive and regulatory functions between the external environment and the internal tissues, including prevention of infection, maintenance of water content level, and reduced penetration of allergens and irritants. 1 The most important function of the skin is providing an effective physical barrier, which consists almost entirely of the epidermis, particularly its superficial layer -the stratum corneum (SC). 1 The SC serves as the principal barrier against the percutaneous penetration of chemicals and microbes. It is involved in the regulation of water release from the SC into the atmosphere, which is known as transepidermal water loss (TEWL). 1 The biophysical parameters of the skin, such as hydration, TEWL, skin surface pH, and elasticity, are all reflections of skin function. 2 Epidermal hydration or SC water content is assessed by measuring the electrical capacitance of the skin with a Corneometer ™ . 3 TEWL is considered to be one of the most relevant markers for measuring skin barrier function. [4][5][6][7]