Raffaella de Salvo

Given the pivotal role played by the microbiome in skin health, it is important to understand how its composition varies with age, sex, and body site and regular use of topical products. Four studies were carried out to determine the effects of long-term (4-week) use of different dexpanthenol-containing topical products on the skin microbiome of a varied population with cosmetically dry skin. The skin microbiome composition was assessed before and after product usage. No significant changes in microbiome richness or diversity were found for the individual test products; however, a meta-analysis of the combined dataset did show changes in microbiome composition as a function of the subject’s sex, age, and body site. The work presented here demonstrates how the use of carefully formulated topical products on skin, when used in a way that is representative of real-life usage conditions, can respect the microbial diversity present on skin across a widely varied study population.

Given the pivotal role played by the microbiome in skin health it is important to understand how its composition varies with age, gender and body site, and regular use of topical products. Four studies have been carried out to determine the effects of long term (4 week) use of different dexpanthenol containing topical products on the skin microbiome of a varied population with cosmetically dry skin. Skin microbiome composition was assessed before and after product usage. No significant changes in microbiome richness or diversity were found for the individual test products, however meta-analysis of the combined dataset did show changes in microbiome composition as a function of subject sex, age and body site. The work presented here demonstrates how the use of carefully formulated topical products on skin, when used in a way which is representative of real life usage conditions, can respect the microbial diversity present on skin across a widely varied study population.

A new dexpanthenol-containing hand cream (ND-HC) was developed for people with dry, sensitive, and/or environmentally stressed hands. To explore the performance and acceptability of ND-HC, we conducted a randomized, intraindividual comparison study in 40 healthy adult subjects with sensitive and very dry skin on the hands. Instrumental measurements determined the effects on stratum corneum (SC) hydration and transepidermal water loss (TEWL) after single and/or 4 weeks’ use of ND-HC. Single and continued at least four times daily applications of ND-HC to very dry skin of the hand for 4 weeks triggered significant increases in SC hydration. On day 29, the mean change in skin capacitance from baseline was significantly greater when ND-HC was applied to the test area compared with the untreated area on the contralateral hand (12.41 vs. 4.46 a.u.; p < 0.001). Upon use of ND-HC over 4 weeks, mean TEWL decreased significantly (bilateral difference: −1.8 vs. 1.0 g/m²/h; p = 0.003), indicating an improvement in SC barrier function. A reduction in dry hand symptoms was observed over the study course. ND-HC was well tolerated and achieved a high level of acceptance and satisfaction. Our findings suggest that ND-HC complies with the required features of a state-of-the-art hand cream.

As new biophysical methods become available to the skin researcher, it is important to understand the type of information that they are capable of measuring, and how it relates to consumer perception of topical moisturizing products. This work was aimed at understanding how two-dimensional (2D) skin hydration mapping can be used to describe skin properties beyond the traditional ‘single number’ approach to skin hydration. Two-dimensional skin hydration measurement data were collected at baseline and after 1 week of in vivo usage of a topical moisturizing product. In addition, subject feedback regarding their skin condition obtained during the study was collected and assessed. Dividing the 2D hydration measurement device images into zones of different electrical permittivity scores enabled analysis of different aspects of the skin compared with traditional electrical skin hydration measurements. Improvement in skin flexibility as a result of use of the topical test product was demonstrated. Complete description of the skin’s hydration state through the creation of hydration histograms to describe its electrical characteristics was performed. Subject feedback data showed improvements in aspects of skin assessed using 2D hydration measurement.

As new biophysical methods become available to the skin researcher it is important to understand the type of information that they are capable of measuring, and how it relates to consumer perception of topical moisturizing products. The aim of the work presented here was to understand what dry skin imaging can reveal about the skin and subject feedback from the use of a topical moisturizing product and how it relates to the consumer usage experience of a topical product. Images from a dry skin camera—the Visioscan^® VC 20plus—during 3 weeks in vivo usage of a topical moisturizing product were analyzed. Subject feedback regarding their skin condition was also collected. Strong statistical improvements (p < 0.05) were observed for a wide range of skin parameters derived from the Visioscan^® VC 20plus. Skin scaliness and smoothness and parameters associated with skin health and appearance (surface, energy, contrast, homogeneity) improved as a result of topical product usage. Subjects reported their skin to feel less dry, to be smoother, and more supple and to look and feel healthier after product usage. The length of time until they felt the need to re-apply the product increased during the study.

Three novel face creams containing dexpanthenol with different lipid contents were developed for dry skin sufferers: a day face cream (DFC), a day face cream with sun protection (DFC-SPF), and a night face cream (NFC). Three identically designed studies (N = 42–44 each) were conducted with healthy adults of three ethnicities (African, Asian, Caucasian) with dry/sensitive skin. Effects on stratum corneum (SC) hydration, SC lipid content, and skin elasticity were quantified by established noninvasive methods during the 4-week studies. After single and repeated once-daily applications of the face creams, facial hydration significantly increased from baseline. On day 28, the mean increments in skin hydration amounted to 27%, 26%, and 27% (p < 0.0001 each) for DFC, DFC-SPF, and NFC, respectively. Favorable effects of DFC, DFC-SPF, and NFC on facial moisturization were observed in all three ethnic groups. The enhancements in SC hydration were not paralleled by improvements in skin elasticity parameters but lipid analyses showed significant increases in SC cholesterol, SC free fatty acid, and/or SC ceramide levels. All three face creams were well tolerated and achieved a high product satisfaction and acceptability by study participants. Our findings support the once-daily use of the face creams in adults of different ethnicities with dry and sensitive skin.

Two novel body/face wash gels enriched with emollient ingredients (including dexpanthenol) were developed for the daily care of dry skin. Two similarly designed 2-week studies (N = 42 each) were conducted to assess the biophysical and cosmetic performance of each of the new wash gels in healthy adults with dry skin. Instrumental measurements quantified the effects of the wash gels on stratum corneum (SC) hydration and transepidermal water loss (TEWL) (with and without a previous sodium lauryl sulfate (SLS) challenge) after single and repeated usage. Following single and repeated applications of the face wash gel to facial skin, as well as to dry SLS-undamaged and SLS-damaged skin of the forearm, skin hydration significantly increased. Similarly, after single and repeated usage of the body wash gel to dry SLS-undamaged and SLS-damaged skin of the forearm, skin moisturization increased significantly from baseline; comparisons with control areas provided inconsistent results for SLS-undamaged skin. No effects on TEWL were observed for either product. Both wash gels were well tolerated and the cosmetic performances were appreciated by the subjects. The study results suggest that daily use of the new wash gels was associated with significant skin-moisturizing effects without adversely affecting skin barrier function and repair.

Three studies were conducted with three new dexpanthenol-containing emollients containing increasing lipid contents (Emollients 1–3) to assess their performances in healthy adults with dry skin. All three studies (N = 42 each) followed virtually the same design. A single skin application of the study product was performed followed by once-daily usage. Skin hydration, transepidermal water loss (TEWL), skin biomechanical properties, and lipid content of the stratum corneum (SC) were regularly assessed over the 28-day study period; a subset (N = 22) underwent a sodium lauryl sulfate (SLS) challenge prior to product application. All three emollients were well tolerated and showed good performances with only minor differences in instrumental measurements. After single and prolonged once-daily applications of Emollients 1–3 to dry skin and dry SLS-damaged skin, skin hydration significantly increased from baseline (BL) (by 38.1–72.4% in unchallenged skin, p < 0.001 for all three). This was paralleled by significant increases in skin elasticity parameters. Usage of Emollients 1 and 3 caused increases from BL in SC cholesterol (by 9.8–12.5%, p < 0.05 for both) and SC free fatty acid levels (by 3.7–26.3%, p < 0.05 for both) at the end of the study. No sustained effects on TEWL were recorded. Our findings support the once-daily use of all three emollients in adults with dry skin.