Depth profiling of epidermal hydration inducing improvement of skin roughness and elasticity: in vivo study by confocal Raman spectroscopy

Abstract

Introduction Skin hydration in the stratum corneum plays an important role in skin condition, and skin efficacy properties are influenced by its hydration level. However, few studies have identified the correlation between changes in skin hydration content and skin characteristics by skin depth level. Aims This study aims to determine how changes in skin hydration at specific depth levels affect skin condition by long‐term tracking changes in hydration of stratum corneum and viable epidermis after usage of moisturizer. Methods Ten volunteers were recruited and subjected to in vivo confocal Raman spectroscopy to perform water content profiling at skin depths of up to 52 μm. Mechanical properties of skin were measured using Cutometer and Antera 3D. Skin‐elasticity and roughness values observed before and after 15 days of moisturizing emulsion use were compared to demonstrate the correlation between observed changes in skin efficacy parameters and skin water content at specific depths. Results Significant increase in relative water content at specific depths was observed in this study. Among mechanical properties of skin, only R4, R6, and R8 parameters demonstrated significant changes. Additionally, rates of change in values of the R6 and R8 parameters revealed a high correlation with water content changes at viable epidermis depths below the stratum corneum. On the other hand, skin roughness parameter showed a correlation with water content changes at the outermost layer of stratum corneum. Conclusion Results of this study indicate that skin elasticity is influenced by its hydration level at viable epidermis depths and skin roughness at stratum corneum each. This suggests that monitoring depth profiles of water content using in vivo confocal Raman spectroscopy provides a breakthrough in tracking the skin efficacy effect of topically applied substances.

In Vitro and In Vivo Characteristics of Olive Oil as Excipient for Topical Administration

“…It is well known that skin hydration in the stratum corneum plays a crucial role in skin condition and, vice versa, that its hydration level influences the skin's efficacy properties. However, few studies have been performed to establish a correlation between modifications in skin hydration content and skin characteristics at different skin depth [33]. For example, the skin hydration measured by the dermoanalyser penetrates to a depth of 10-20 µm of the stratum corneum [28].…”

“…For example, the skin hydration measured by the dermoanalyser penetrates to a depth of 10-20 µm of the stratum corneum [28]. It has been demonstrated that skin elasticity is influenced by its hydration level at viable epidermis depths, while skin roughness is more affected by hydration at the stratum corneum level [33]. This highlights the importance of determining the effect of topically applied formulations on hydration at the stratum corneum and of monitoring skin elasticity or the depth profile of water content using other techniques such as Raman spectroscopy.…”

Efficacy and Safety of the Genistein Nutraceutical Product Containing Vitamin E, Vitamin B3, and Ceramide on Skin Health in Postmenopausal Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

“…When the facial skin around the pores is properly hydrated, the stratum corneum inside and surrounding the pores swells, and the size of the pores and their surface area are reduced accordingly [ 44 ]. Since skin elasticity is partly influenced by skin hydration levels at viable epidermis depths and skin roughness at the stratum corneum, it is conceivable that the GEN product may lead to enhanced skin elasticity as well [ 45 ]. However, the present study had no parameters representative of skin elasticity, so the benefit of the GEN product on this feature may require further investigation.…”

Vacuum and electromagnetic field in synergy for skin rejuvenation: A retrospective study on 217 patients

“…A possible limitation of this study derives from the fact that specific measurements of skin elasticity, an important parameter for the analysis of skin rejuvenation, were not performed. However, given that skin hydration levels are strongly correlated with skin elasticity, 24 the improvement recorded in hydration levels can be considered an indirect index of the improvement in the degree of elasticity.…”

“…However, given that skin hydration levels are strongly correlated with skin elasticity, 24 the improvement recorded in hydration levels can be considered an indirect index of the improvement in the degree of elasticity.…”