DSM Nutritional Products Ltd, P.O. Box 2676, Bldg. 203.4/86, CH-4002, Basel, Switzerland.
Newtone Technologies, 13bis, place Jule Ferry, 69006, Lyon, France.
Int J Cosmet Sci. 2019 Oct;41(5):411-424. doi: 10.1111/ics.12562. Epub 2019 Aug 30.
Dry skin is one of the most important concerns of consumers worldwide. Despite huge efforts over several decades, the personal care industry still does not offer a perfect solution to satisfy the unmet needs of consumers for moisturising treatments in different ethnic groups. The paucity of data for the underlying cellular and biochemical problems in, and the effects of moisturisers on photodamaged facial skin may partly explain this. Mainly, single point measurements are used to understand the effects of products on skin physiology even on surrogate skin sites such as the non-photodamaged volar forearm. Some groups have developed discontinuous facial maps of skin biophysical properties, however, in 2014 a continuous facial analysis of bio-instrumental evaluations was developed using a heat map approach. These maps enabled a continuous visualization of features that not only revealed an unexpected complexity of facial skin but also indicated that use of surrogate skin sites for facial skin is inappropriate. We have demonstrated that remarkable gradients of skin hydration, TEWL, skin surface pH and sebum exist within short distances across the face and the gradients are distinctive among different ethnic groups. In addition, these studies have demonstrated that darkly-pigmented individuals do not necessarily have a better skin barrier function than their less-pigmented counterparts and that Caucasians have a lower facial skin surface pH compared with more pigmented subjects. Overall, there are no correlations between capacitance, TEWL and skin surface pH including individual topology angle values. Novel 3D camera approaches have also been used to facilitate a more precise assignment of measurement sites and visualisation. The 3D facial colour mappings illustrated precisely the local moisturising effects of a moisturising cream. There were subtle ethnic differences in efficacy that may be related to underlying skin biochemistry and/or ethnic differences in product application. A placebo-controlled study using conductance measurements in Chinese subjects is also reported. Finally, a new whole face statistical approach has been taken to prove differences in skin parameters but also of moisturiser treatment that adds further to our understanding of the ethnic differences in skin physiology and product application. This paper reviews the background of the development and application of this methodology.
皮肤干燥是全球消费者最关注的问题之一。尽管几十年来付出了巨大努力，但个人护理行业仍未提供完美的解决方案来满足不同种族消费者对保湿治疗的未满足需求。这在一定程度上可以解释为什么有关光损伤面部皮肤的潜在细胞和生化问题以及保湿剂对其的影响的数据仍然很少。主要是，人们使用单点测量来了解产品对皮肤生理学的影响，即使是在替代皮肤部位（如非光损伤的掌侧前臂）也是如此。一些研究小组已经开发出了皮肤生物物理特性的不连续面部图谱，然而，在 2014 年，人们采用热图方法开发了一种连续的面部生物仪器评估分析方法。这些图谱能够连续可视化特征，不仅揭示了面部皮肤出人意料的复杂性，还表明使用替代皮肤部位来评估面部皮肤是不合适的。我们已经证明，在面部的短距离内，皮肤水合度、TEWL、皮肤表面 pH 值和皮脂存在显著的梯度，并且在不同种族之间这些梯度具有独特性。此外，这些研究还表明，深色皮肤的个体皮肤屏障功能不一定比浅色皮肤的个体更好，与色素较多的个体相比，白种人的面部皮肤表面 pH 值较低。总体而言，电容、TEWL 和皮肤表面 pH 值之间没有相关性，包括个体拓扑角度值。新型 3D 相机方法也已被用于更精确地分配测量部位和可视化。3D 面部彩色图谱精确地说明了保湿霜的局部保湿效果。在功效方面存在微妙的种族差异，这可能与皮肤内在的生化特性以及产品应用中的种族差异有关。本文还报道了一项在中国受试者中使用电导测量进行的安慰剂对照研究。最后，采用全新的全脸统计方法来证明皮肤参数以及保湿剂处理的差异，这进一步加深了我们对种族间皮肤生理学和产品应用差异的理解。本文综述了该方法的发展和应用背景。
