Hydration, so useful for our skins, so present in cosmetic products sales points, may be improved, thanks to specific active ingredients. There is currently plenty of choice. Which ones to choose, and for which purpose? This was the topic of a lecture by Christine Lafforgue, from the Dermopharmacology and Cosmetology Unit of the University of Paris Sud 11, during the 12th Journées d’Echanges Scientifiques et Techniques (JEST: Scientific and Technical Exchanges Convention), held on 12 October 2012, in Montpellier, Southern France.
The natural hydration of our skins, which reflects their good health and their beauty, is a complex phenomenon: CosmeticOBS-L’Observatoire des Cosmétiques has already fingered this point in its A trip in the core of moisturization article.
First, Christien Lafforgue reminded the audience of the importance of an exogenic support of this process, giving some data and figures:
• the stratum corneum (the upper layer of the epidermis) contains circa 15% of water; its surface is dryer than the lower layers, and it may absorb up to six times its weight of water;
• a square centimeter contains more than 600,000 cells (3,900,000 cells per square inch), which each requires a water supply;
• trans-epidermal water loss (TEWL) is a factor of cutaneous dryness, which may be dramatically increased when skin is dry or exposed to sun;
• the ability of the skin to retain its water diminishes when ageing;
• the surface quality of a dry skin leads to a rugged micro-relief, a high roughness, an irregular shedding …
Which kind of formulation, with which active ingredients, shall be designed to provide the skin with a complementary hydration, to replace lost water, to improve its balance and comfort?
Christine Lafforgue …
