Make-up Product Research Laboratory, Kao Corporation, Odawara, Japan.
Biological Science Laboratory, Kao Corporation, Odawara, Japan.
Int J Cosmet Sci. 2021 Apr;43(2):158-164. doi: 10.1111/ics.12677. Epub 2021 Mar 31.
Lips can easily become dry and rough, one reason being the characteristics of their ceramide (CER) profile. Lips have lower levels of total ceramides, higher percentages of CER[NS] and CER[AS], and lower percentages of CER[NP] and CER[NH] than skin in other regions of the body. The purpose of this study was to clarify the effects of synthetic pseudo-ceramide (pCer; Cetyl-PG hydroxyethyl palmitamide) to improve the dryness and roughness of the lips of healthy subjects in a formulation that exclude an occlusive effect.
Thirty-one Japanese female subjects with normal skin (age range 21-37 years; mean 28.6) were enrolled in this study. A four-week continuous use test was conducted using samples with or without 0.5% or 2.0% pCer. The degree of lip roughness was scored, and values of capacitance, transepidermal water loss (TEWL) and lip surface elasticity were measured. Endogenous CER profiles and absorption levels of pCer in the stratum corneum (SC) were analysed in tape-stripped skin specimens.
Treatment with the pCer-2.0% sample significantly improved the visual roughness score after 2 and 4 weeks compared to 0 weeks and compared to the Blank. Moreover, an improvement in TEWL was observed after 4 weeks of treatment with the pCer-2.0% sample. CER[NP] showed a significant increase in pCer-2.0% treated lips after 4 weeks compared to the Blank. Both pCer-0.5% and pCer-2.0% were significantly absorbed after 2 weeks compared with the Blank.
The effect of the synthetic pseudo-ceramide pCer to improve the roughness of lips was shown excluding the effect of occlusiveness derived from the formulation for the first time. Since the improvement of TEWL and absorption of pCer was observed, we concluded that pCer was first absorbed in rough lip areas, improved the ceramide profile and consequently restored the barrier function.
嘴唇容易变得干燥和粗糙，原因之一是其神经酰胺（CER）谱的特征。嘴唇的总神经酰胺含量较低，CER[NS]和 CER[AS]的百分比较高，而 CER[NP]和 CER[NH]的百分比较低，与身体其他部位的皮肤相比。本研究的目的是阐明合成假神经酰胺（pCer；十六烷基-PG 羟乙基棕榈酰胺）的作用，以改善健康受试者嘴唇的干燥和粗糙程度，同时排除制剂的封闭作用。
本研究纳入 31 名日本女性健康受试者（年龄 21-37 岁；平均 28.6 岁）。使用含有 0.5%或 2.0% pCer 的样品进行为期四周的连续使用试验。对嘴唇粗糙度进行评分，并测量电容、经皮水分流失（TEWL）和嘴唇表面弹性。分析胶带剥离皮肤标本中的内源性 CER 谱和角质层（SC）中 pCer 的吸收水平。
与 0 周和空白相比，pCer-2.0%样品治疗 2 周和 4 周后，视觉粗糙度评分明显改善；与空白相比，pCer-2.0%样品治疗 4 周后 TEWL 也有所改善。与空白相比，pCer-2.0%处理的嘴唇中 CER[NP]在 4 周后显著增加。pCer-0.5%和 pCer-2.0%在 2 周后与空白相比均显著吸收。
首次证明了合成假神经酰胺 pCer 改善嘴唇粗糙度的效果，排除了制剂的封闭作用。由于观察到 TEWL 的改善和 pCer 的吸收，我们得出结论，pCer 首先被吸收到粗糙的嘴唇区域，改善了神经酰胺谱，从而恢复了屏障功能。
