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Skin Barrier Impaired? Two ‘TEWLs’ to Tell via Cosmetics & Toiletries

January 3, 2017  By: Yi Ann Den, Slobodanka Tamburic, Mustafa Varcin, Caroline Searing and Melissa Chan, London College of Fashion, University of the Arts London, UK

The lipid matrix of the stratum corneum (SC), consisting primarily of ceramides, cholesterol and fatty acids, is crucial for the integrity of the skin barrier. Linoleic acid is an essential fatty acid, whose deficiency can lead to abnormal epidermal permeability barrier function.1, 2 In the case of its deficiency, linoleic acid is replaced with oleic acid, disturbing the normal formation of lipid lamellae in the SC.3

It has been proposed that topical treatment of linoleic acid could repair defective barrier function in detergent-treated skin.1 In addition, it has been shown that topical application of fatty acids in general could alter the intercellular lipid domains of the SC.4 A range of commercial and newly developed topical products containing linoleic acid was therefore used in the present study to assess, via transepidermal water loss (TEWL), the proposed effects:
– The protection potential, whereby the products are applied for a period of time before the insult to the skin barrier is carried out; in this case with sodium lauryl sulfate (SLS) solution; and
– The repair potential, whereby an insult with SLS to the skin barrier was followed by a period of product application.

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