Muizzuddin Neelam, Marenus Kenneth D., Maes Daniel H.
Ester Lauder Companies, Melville, NY, USA.
Skin Res Technol. 2000 Nov;6(4):199-204. doi: 10.1034/j.1600-0846.2000.006004199.x.
BACKGROUND/AIMS: Although there is an increasing awareness of the detrimental effects of solar irradiation on skin, a tanned look is still in fashion. To achieve the tanned look without sun exposure various sunless tanning formulations have become available. Most of these contain dihydroxyacetone (DHA) which binds to the proteins of the stratum cornium and imparts a brown color to skin. This color is similar to a suntan but can be somewhat more yellow, making it appear unnatural. The aim of this study was to determine a quantitative method to define a "natural" tan and to study methods to improve the tonality of sunless tanning on skin. METHODS: Tonality of suntan was determined as the marker for a "natural" tan. In order to achieve this, human volunteers were exposed to the sun and the change in skin color was observed after 3 days. Color measurements obtained with the Minolta Chromameter were plotted in two standard graphs labeled as the "natural universe of tan", which depicted a balance between Chroma and change in reflectance, while the "natural universe of color" determined the balance between changes in yellow and red components of the suntan. Change in skin color after treatment with DHA was then inserted in these graphs to observe how "natural" the tonality of sunless tan appeared relative to suntan. RESULTS: Results show a good balance between Chroma and change in reflectance for suntanned skin in the "natural universe of tan". Conversely, the "natural universe of color" exhibited a good balance between increase in yellow and red components of suntan. Sunless tan data inserted in these graphs showed that for several subjects with skin types I-II the tonality is not within the realm of "natural" but is unnaturally yellow. Addition of antioxidants, especially caffeic acid phenethyl ester (CAPE) in DHA formulation significantly shifted the tonality towards the center of the "natural universe of color". CONCLUSIONS: The "natural universes of tan and color" exhibit a simple and quantitative assessment of tonality of suntan and sunless tan. Although skin tonality from DHA-induced sunless tan can often lie outside the realm of the "natural" tan, it is possible to improve this tonality to a more "natural" look by addition of strong antioxidants in the DHA formulations.
背景/目的：尽管人们越来越意识到阳光照射对皮肤的有害影响，但晒黑的肤色仍然很流行。为了在不暴露于阳光下的情况下获得晒黑的效果，各种免晒美黑配方已经出现。其中大多数含有二羟基丙酮（DHA），它与角质层中的蛋白质结合，使皮肤呈现棕色。这种颜色类似于晒黑的肤色，但可能会更偏黄一些，显得不自然。本研究的目的是确定一种定量方法来定义“自然”晒黑，并研究改善皮肤免晒美黑色调的方法。
将晒黑的色调确定为“自然”晒黑的标志。为了实现这一点，让人类志愿者暴露在阳光下，并在3天后观察皮肤颜色的变化。用美能达色差仪获得的颜色测量值绘制在两个标准图表中，分别标记为“晒黑的自然范围”，它描绘了色度与反射率变化之间的平衡，而“颜色的自然范围”则确定了晒黑的黄色和红色成分变化之间的平衡。然后将用DHA处理后皮肤颜色的变化插入这些图表中，以观察免晒美黑的色调相对于晒黑的肤色看起来有多“自然”。
结果表明，在“晒黑的自然范围”中，晒黑皮肤的色度与反射率变化之间有良好的平衡。相反，“颜色的自然范围”显示出晒黑的黄色和红色成分增加之间有良好的平衡。插入这些图表中的免晒美黑数据表明，对于一些皮肤类型为I-II的受试者来说，其色调不在“自然”范围内，而是不自然地偏黄。在DHA配方中添加抗氧化剂，尤其是咖啡酸苯乙酯（CAPE），可使色调明显向“颜色的自然范围”中心偏移。
“晒黑和颜色的自然范围”展示了对晒黑和免晒美黑色调的简单定量评估。尽管DHA诱导的免晒美黑的皮肤色调通常可能不在“自然”晒黑的范围内，但通过在DHA配方中添加强抗氧化剂，可以将这种色调改善为更“自然”的外观。
