Oral fish cartilage polysaccharides in the treatment of photoageing: biophysical findings

The topically applied cosmetic products can be helpful in improving the aged skin condition. The present study shows how oral fish-cartilage food supplementation can be helpful in improving the treatment of ageing skin. A total of 30 healthy women with signs of skin ageing were studied. Fifteen of the women were treated with a food supplement based on polysaccharides derived from the fish cartilage and a natural mix of antioxidants for 2 months and the other 15 with a placebo. Clinical evaluation and biophysical parameters related to skin function and wrinkle severity, such as silicone replica, skin thickness, mechanical properties, skin colour and capacitance, were measured. The results showed statistically significant changes in the active-treated group in comparison to the placebo. In particular, dermal thickness (treatment: from 1.13 to 1.23 mm; P < 0.001), skin wrinkling (treatment: from 9.5 to 3.5 R(a); P< 0.002), skin colour (treatment: brighter and less pigmented; P < 0.02) and viscoelasticity (treatment: from 0.70 to 0.97%; P < 0.02) showed considerable improvement. Most of these parameters are related to changes occurring within the dermal matrix, which is improved after the treatment, whereas most of the topically applied cosmetic products have a short-term effect on superficial structures. A combination treatment (oral and topical) can be more effective in reducing the signs of skin-ageing.     

The moisturizing effect of a wheat extract food supplement on women’s skin: a randomized,double‐blind placebo‐controlled trial

Ceramides, specific lipid components of the skin, represent 35–40% of the intercellular cement binding cells together and contributing to skin hydration. A wheat extract rich in ceramides and digalactosyl‐diglycerides was developed by Hitex in two forms: wheat extract oil (WEO) and wheat extract powder (WEP). In vitro tests and two clinical studies demonstrated promising efficacy results with WEP on skin hydration. To confirm these early results, a double‐blind, randomized, placebo‐controlled study was carried out on 51 women aged 20–63 years with dry to very dry skin who received either 350 mg of WEO or placebo for 3 months. Evaluation of skin hydration on legs, arms and face, assessed at baseline (D0) and at study end (D84) was performed by the dermatologist using dermatological scores (dryness, roughness, erythema), skin hydration measurement (corneometry) and self‐assessment scores (Visual Analogue Scale: VAS). Perceived efficacy was noted by participants throughout the study; tolerability and overall acceptability of the study products were evaluated by the dermatologist and the participants at the end of study. Skin hydration was significantly increased between D0 and D84 on the arms (P < 0.001) and legs (P = 0.012) in the WEO group compared with placebo. Even if no significant statistical differences between groups were observed for the dermatological evaluation, skin dryness and redness tended to be reduced in the WEO group. Moreover, from D0 to D84, the VAS index had a tendency to increase in favour of WEO for the overall skin hydration (P = 0.084) indicating that participants perceived an improvement. The WEO capsules were perceived by participants as being more effective than placebo on all skin dryness signs. In conclusion, WEO capsules were well tolerated and appreciated. After 3 months’ treatment, a significant increase in skin hydration and an improvement in associated clinical signs were observed in women with dry skin.     

Effects of topical gluco-oligosaccharide and collagen tripeptide F in the treatment of sensitive atopic skin

Sensitive skin is a dermatological problem of increasing incidence in western countries and is sometimes associated with atopic condition and bacterial sovrainfection. The purpose of this study is to evaluate in a double blind, randomized, placebo controlled trial the efficacy of gluco-oligosaccharide and collagen tripeptide F in controlling the signs and symptoms of sensitive atopic skin. Forty female subjects (age, 30–59 years) affected by non-lesional atopic sensitive skin entered the study. Skin sensitivity was determined by a dermatologist on the basis of medical history, stinging test, dermatological examination and a questionnaire. A treatment with the test products (active and placebo) was carried out for 4 weeks. Measurements and clinical evaluation were carried out at baseline and at the end of the study. The following objective parameters investigated were bacterial count, skin pH and colour, transepidermal water loss (TEWL), stratum corneum hydration, skin roughness and mechanical properties. Clinical assessment included also a scoring system for dryness, desquamation, irritation, erythema and papules. Significant differences were found in the active treated group when compared with the placebo and in particular for instrumental parameters of roughness ( P  < 0.02), volume ( P  < 0.01), TEWL ( P  < 0.02), erythema ( P  < 0.0006) and clinical parameters of dryness, desquamation and irritation ( P  < 0.001). Moisturization levels and skin colour improved significantly in both the active and placebo groups. In conclusion, the study shows that the modulation of bacterial proliferation and normalization of skin barrier properties and stratum corneum moisturization can improve the symptoms of sensitive skin.     

An oral nutraceutical containing antioxidants, minerals and glycosaminoglycans improves skin roughness and fine wrinkles

Various nutraceuticals (dietary supplements) are claimed to have cutaneous antiageing properties, however, there are a limited number of research studies supporting these claims. The objective of this research was to study the effectiveness of an oral nutraceutical containing antioxidants, minerals and glycosaminoglycans on cutaneous ageing. In this double-blind, placebo-controlled trial, 60 women aged 35–60 years were randomized to receive oral dietary supplement ( n  = 30) or placebo ( n  = 30), once daily for 12 weeks. The depth of skin roughness and fine wrinkles were measured using surface evaluation of skin parameters for living skin (Visioscan) at baseline, and at the 4, 8 and 12 weeks of treatment. Surface evaluation using a replica film (Visiometer) at baseline and at the 12th week of treatment was also carried out. Statistical differences in objective skin improvement were assessed by the independent t -test. The volunteers' satisfaction was tested using the chi-squared test. The baseline depth of skin roughness and fine wrinkles in the treatment group and the placebo group were 100.5 and 100 μm, respectively. At the end of the study, the depth of skin roughness and fine wrinkles in the treatment group showed a 21.2% improvement, whereas improvement in the control group was 1.7%. This difference was statistically significant ( P  < 0.001). With regard to the volunteers' satisfaction, there was no statistically significant decrease in the homogenization of skin colour, however, a statistically significant reduction in pore size and depth of skin roughness and fine wrinkles were observed ( P  < 0.05). No side effects were noted throughout the study. The oral dietary supplement containing antioxidants, minerals and glycosaminoglycans improved skin roughness and fine wrinkles but did not affect skin colour change in female volunteers.     

Quantification of the skin's topography by skin profilometry

A method of skin profilometry is presented. The data generated using this method are used to (a) uncover sources of variation in skin profilometry, (b) provide information regarding the choice of roughness parameters best suited for characterizing the skin's topography, and (c) determine if skin profilometry is a valuable tool for quantitatively assessing changes in the skin's surface pattern.
The data show the roughness parameter values to be dependent on the orientation of the tracings with regard to the major grooves and ridges present in the surface patterns. Large variabilities of roughness parameter values obtained for multiple scans within small areas of replicas are indicative of the nonhomogeneity of the skin's surface. The number of peaks, mean peak size, mean depth of roughness, depth of smoothness, and residual profile length appear to be the most utile roughness parameters for quantifying changes in the skin's topography. The ability of skin profilometry to detect subtle changes in the skin's surface pattern due to hydration indicates the method is a sensitive means of quantifying the skin's topography.
Quantification de la topographie de la pedu par la profilométrie de la pedu     

Chitin–glucan,a natural cell scaffold for skin moisturization and rejuvenation

Two clinical studies were conducted to evaluate the tolerance and effects of a copolymer of chitin and beta‐glucan, forming the exoskeleton of fungal cell walls, now supplied for cosmetic applications. A 6‐week randomized, double‐blind, placebo‐controlled study was conducted on 13 volunteers with sensitive skin to compare with 0.5–2% formulations chitin–glucan applied twice daily. Biometrological evaluations showed that erythema did not develop, the water retention capacity of the stratum corneum increased and the transepidermal water loss moderately decreased. Another 16‐week randomized, double‐blind, placebo‐controlled study was conducted on 20 men showing signs of ageing skin. A 1.5% chitin–glucan formulation was applied twice daily. Objective biometrological assessments showed a progressive increase in skin firmness and stratum corneum hydration when desquamation and skin roughness decreased. In conclusion, the chitin–glucan formulations appear safe. They significantly mitigate some signs of skin ageing and improve both stratum corneum hydration and skin barrier function.     

Skin improvement and stability of Echinacea purpurea dermatological formulations

Echinacea purpurea contains many beneficial constituents for protection of skin from oxidative stress and for improving hydration of skin. This study aimed to investigate the stability and dermatological efficacy of E. purpurea cream and gel. Echinacea purpurea extract was incorporated into suitable cream and gel bases. Stability of the extract in the formulations was investigated by determining its residual total phenolic content and antioxidant activity after storage at 4°C, 30°C and 40°C for 6 months. The effect of those formulations on skin irritation, hydration level and wrinkle reduction was evaluated in 10 healthy volunteers, aged 25–40 years. The shelf lives of E. purpurea cream and gel in terms of total phenolic content and antioxidant activity were only 2 and 4 months respectively at 4°C and could be extended up to 7 months by incorporation of α‐tocopherol or disodium editate. The corneometer hydration indices increased up to 10.6 AU and 11.4 AU, and the wrinkles decreased 9.47% and 14.92% because of the application of E. purpurea cream and gel for 1 month. Both formulations showed no irritation to skin. Echinacea purpurea cream and gel developed in this study were effective in improving skin hydration and reducing wrinkle, but showed low storage stability.     

The influence of a cream containing 20% glycerin and its vehicle on skin barrier properties

Glycerin is widely used in cosmetics and well as in pharmaceutical formulations, mainly as humectant. In vitro studies have shown glycerin to prevent crystallization of stratum corneum model lipid mixture at low room humidity. Whether this may affect the skin barrier function during repeated application of glycerin in a cream base to normal skin is not known. Therefore, the influence of a cream containing 20% glycerin was compared with its placebo cream in a bilateral, double-blind study on 17 healthy volunteers. The effect was evaluated as influence on hydration with a corneometer and on skin barrier function. Skin barrier function was assessed as permeability to water with an evaporimeter (transepidermal water loss; TEWL) and as sensitivity to an irritating surfactant by measuring the biological response (measured as TEWL and skin blood flow). Ten days treatment of normal skin with 20% glycerin significantly increased skin corneometer values, indicating an increased hydration. However, our study failed to show an influence of glycerin on human skin, in terms of TEWL and skin sensitivity to SLS-induced irritation.     

水解胶原蛋白果饮的试食试验研究

为观察口服自制水解胶原蛋白果饮对女性肤质水分的调节作用,进行8周人体试食的试验研究,结果显示试食组（14名健康成年女性）4周后脸颊、前臂和腿的皮肤水分与试食前自身对照有显著性提高,8周后试食组前额、脸颊、前臂和腿的皮肤水分与试食前自身对照均有显著性提高,说明该水解胶原蛋白果饮具有改善皮肤水分的功能作用。     

Comparative effectiveness of α-hydroxy acids on skin properties

A number of α-hydroxy acids, including glycolic, lactic ( l (+) and d (–) forms) citric, hydroxybutyric and malic acids, were evaluated for their effects on various skin properties at concentrations of 0.5–1.15 m . The acids were evaluated for their stinging potential on sensitive skin, the ability to increase skin cell renewal, and their ability to improve moisture content and reduce lines and wrinkles over a six-week period. Results indicated that lactic l (+) and glycolic were the most effective acids when tested at equimolar concentrations. Both materials were less irritating than the d (–) lactic acid form and the other acids tested. Even though with long-term use both d (–) and l (+) lactic acid and glycolic acid produced comparative improvements in skin hydration and lines and wrinkle improvement, the l (+) form of lactic acid did so with fewer consumer complaints than any of the other acids tested. When the concentration of lactic and glycolic acids was increased to more than 1.5 m a greater difference in irritation potential was observed with respect to stinging, with the l (+) form of lactic acid being less irritating than glycolic acid and the d (–) form. Our results suggest that l (+) and d (–) lactic acid and glycolic acid are the two most effective materials for developing α-hydroxy acid products. Lactic acid has a slight technical advantage over glycolic acid. Both l (+) and the d (–) forms are better moisturizers when fully or partially neutralized. Moreover the l (+) form is also less irritating than d (–) and glycolic acid. Other acids such as citric, malic, and hydroxybutyric acids appear to be less effective materials but may be useful additions to lactic or glycolic acid mixes.     

Multicentre comparison of skin hydration in terms of physical-, physiological- and product-dependent parameters by the capacitive method (Corneometer CM 825)

A multicentre study for measuring skin hydration with 349 volunteers was carried out in six different laboratories. The purpose of the study was to investigate physical-, physiological- and product-dependent parameters of three test emulsions (base, base + moisturizer and base + moisturizer + lipids) in a double-blind study. A comparison between analogous and digital sensor technology of the Corneometer CM825 was examined. Here, a clear relationship between both sensor types could be highlighted. A vital point of the study was the division of the test subjects according to their skin type. To get more objective limits for three different skin types - very dry, dry and normal skin - visual expert evaluation, self-assessment and hydration measurements were analysed by means of statistical methods. The moisture-related skin types were determined as follows: very dry skin was characterized with corneometer units below 30, dry skin between 30 and 40 and normal skin higher than 40 a.u. (arbitrary units). The efficacy of the three test emulsions was examined in relation to the mentioned skin types. Analysing the measured data of all test centres, a clear dependency of skin physiology (skin type) and product efficacy became evident. The drier the skin, the higher the increase of hydration. The product performance of the three test emulsions compared to the untreated control resulted in a significant increase of skin hydration in all measuring centres. The evaluation of a product ranking showed a good differentiation between the basic emulsion and the two other products. An increase of efficacy by adding lipids could be observed in four of six centres. The important influence of the skin type of the volunteers on the degree of product performance, as demonstrated in this study, should be especially considered when drawing up guidelines for efficacy testing.     

Systemic evening primrose oil improves the biophysical skin parameters of healthy adults

Biophysical skin parameters are indicators of age-related structural and functional changes in skin tissues. This randomized, double-blind, placebo-controlled study in healthy adults tested the effect of Efamol evening primrose oil [EPO, a gamma-linolenic acid (GLA) containing vegetable oil] on skin moisture, transepidermal water loss (TEWL), redness, firmness, elasticity, fatigue resistance and roughness. Efamol EPO was administered orally in soft gel capsules, 3 x 500 mg b.i.d. for 12 weeks. Measurements were taken at baseline and at weeks 4 and 12. The two treatment groups did not differ at baseline and at week 4. At week 12, however, all measured variables, with the exception of skin redness, were significantly different in the EPO group compared with placebo. Skin moisture, TEWL, elasticity, firmness, fatigue resistance and roughness had significantly improved by 12.9, 7.7, 4.7, 16.7, 14.2 and 21.7%, respectively. The two-sided levels of significance in favor of the EPO treatment ranged between 0.034 and 0.001. These findings lend further support to the notion that GLA is a conditionally essential fatty acid for the skin, i.e. it is unable to synthesize GLA, and therefore depends on preformed GLA for optimal structure and function.     

A poster of this work was presented at the 23rd IFSCC Congress 2004, Orlando, Florida, USA

The aim of the study was to evaluate the efficacy of polysaccharides from fish cartilage with regard to their skin aging properties. An application test was carried out during the intake of cartilage tablets as a nutritional supplement. The study was designed as a monocentric, double-blind, randomized, placebo-controlled application test. 28 healthy female volunteers (35–60 years) with dry skin were included in the study. They were divided into two groups. Group 1 received tablets containing placebo and group 2 the verum treatment (cartilage hydrolysate combined with vitamin C). The duration of the study was 12 weeks. The focus of interest was to find out about the hydration properties, and to see whether the skin barrier and structure were influenced by the test formulation compared with placebo. Hydration measurements were made before and during the study, and the transepidermal water loss (barrierer function of the skin) was measured. The thickness and density of the skin of all volunteers were determined by means of ultrasound measurements during the study. Statistical analysis was based on Wilcoxon signed rank test. The following results were obtained in this study: there was a significant improvement in the hydration properties, a significant decrease in transepidermal water loss and a significant increase in the skin density in the verum group (cartilage extract). No or minor improvements could be detected in the placebo group.     

Role of topical and nutritional supplement to modify the oxidative stress

Background: Evidence suggests that signs of skin ageing such as wrinkling, ragging and actinic lentigines, may be connected to cumulative oxidative damage incurred throughout our lifetimes. To counteract this oxidative injury, skin is equipped with a network on enzymatic and non-enzymatic antioxidant systems, such as tocopherols, ascorbate polyphenols. All these compounds administered topically by cosmetics or by oral route by diet supplements, have been shown to exert an antioxidant/protective effect in skin or skin cells. Objective: The object of this study was to evaluate both in vitro and in vivo the activity performed by different topical antioxidants and nutritional supplements. Methods: A randomized double-blind placebo-controlled study was carried out for 8 weeks on 30 dry-skinned elderly volunteers, women aged between 48 and 59 years, with moderate xerosis and photoageing. Surface skin lipids, skin hydration and MDA determination were topically detected by 3C System. ROS was evaluated on the blood serum and on IL-3 stimulated human leukocytes by ROS Meter System at 505 nm. All the subjects applied twice a day for 2 months a nanocolloidal gel and/or take a diet supplement by oral route at the quantity of two capsules per day. All the formulations used were antioxidant-enriched (ascorbic acid, tocopherol, alpha-lipoic acid, melatonin, emblica). Results: Oxidative stress and consequently lipids peroxidation decreased from 30 to 40% (P < 0.005) in blood serum of all the subjects treated with antioxidant compounds topically and by oral route. Both free radicals recovered in blood serum and on skin (in vivo) and ROS induced by irradiation of leucocytes with UVB light (in vitro), appear sensibly lower in subjects antioxidant-treated. Conclusions: From the obtained data, it seems possible to conclude that all the compounds used play interesting role as topical and systemic photoprotectants, thanks to their interesting antioxidant property. Moreover, the antioxidant treatment seems to be a promising therapeutic approach also in reducing the oxidative stress of people affected by photoaging.     

Influence of skin cleansing preparation acidity on skin surface properties

Two long-term trials were conducted each over eight weeks to compare the effect of the regular application of skin cleansing preparations of pH 5.5 and pH 8.5 and pH 5.5 and pH 7.0 respectively on the surface pH, roughness and transepidermal water loss (TEWL) of normal human forehead and forearm skin. Both trials were based on a cross-over design: five healthy volunteers started with a pH 5.5 preparation and switched to the other after four weeks, five additional volunteers used the preparations in the opposite order. While the skin surface pH was markedly lower in those individuals using the pH 5.5 preparation at each examination, as compared to those using the pH 8.5 or pH 7.0 preparation, no such difference could be established with respect to skin roughness and TEWL. Hence the skin irritancy of a cleansing preparation does not seem to be linked to its pH within the pH ranges tested.     

Age‐related changes in skin barrier function – Quantitative evaluation of 150 female subjects

The protection against water loss and the prevention of substances and bacteria penetrating into the body rank as the most important functions of the skin. This so‐called ‘skin barrier function’ is the natural frontier between the inner organism and the environment, and is primarily formed by the epidermis. An impairment of the skin barrier function is often found in diseased and damaged skin. An influence of ageing on skin barrier function is widely accepted, but has not been conclusively evaluated yet. Therefore, the aim of this clinical study was to assess the potential influence of ageing on skin barrier function, including transepidermal water loss (TEWL), stratum corneum hydration, sebum content and pH value. One hundred and fifty healthy women aged 18–80, divided into five age groups with 30 subjects each, were evaluated in this study. TEWL, hydration level, sebum secretion and pH value of hydro‐lipid acid film were measured with worldwide acknowledged biophysical measuring methods at cheek, neck, décolleté, volar forearm and dorsum of hand. Whereas TEWL and stratum corneum hydration showed only very low correlation with subject's age, the sebum production decreased significantly with age, resulting in the lowest skin surface lipids levels measured in subjects older than 70 years. The highest skin surface pH was measured in subjects between 50 and 60 years, whereas the eldest age group had the lowest mean pH. The dorsum of the hand was the location with the highest TEWL and lowest stratum corneum hydration in all age groups. The results show that only some parameters related to skin barrier function are influenced by ageing. Whereas sebum production decreases significantly over lifetime and skin surface pH is significantly increased in menopausal woman, TEWL and stratum corneum hydration show only minor variations with ageing.     

Hydration of the stratum corneum

Topically applied water, occlusion and topically applied glycerol were used to investigate and characterize some of the changes which occur in the hydrated stratum corneum. The effects of these treatments were monitored using non-invasive techniques under controlled conditions. The Servomed Evaporimeter was used to determine natural water flux from the skin surface before and after treatment. The performance of the Evaporimeter in this type of study had previously been improved by attaching a paper baffle to the detector. This eliminated the variance in output caused by atmospheric movement. Experiments were carried out at temperatures below the threshold of thermal sweating and emotional sweating was minimized. Skin surface topography was characterized by means of a new type of profilometer. The instrument's design allowed a diamond stylus to traverse the living skin surface without significantly altering its structure. Changes in skin surface roughness were further elucidated using scanning electron microscopy and macrophotography. In vivo penetration of glycerol was assessed by chemical analysis of stratum corneum layers of treated skin. Samples were obtained by sequential stripping of the stratum corneum using adhesive tape. Topically applied water produced only a transient benefit because of rapid evaporation. More prolonged hydration was achieved by suppressing transepidermal water loss with polyethylene film. This occlusive hyperhydration was characterized by a significant reduction in profile roughness and by a smoother macroscopic appearance. Glycerol achieved the same effects by reducing the magnitude of the natural water flux from the skin surface and by reducing the rate of evaporation of water from applied aqueous glycerol solution or cosmetic product. Both effects were seen as the result of lowered water activity in the proximity of glycerol. Smoothing effects of glycerol on the skin surface, and improved appearance, persisted for at least 24 h. This persistence was explained by evidence for diffusion of glycerol into the stratum corneum where it formed a reservoir. Hydration of the skin is known to affect its barrier function and thereby exert a profound effect on penetration of both lipophilic and hydrophilic molecules. Clinically, this effect may be achieved using liberal applications of occlusive petroleum jelly and ointments. The results presented in this paper suggest that the use of humectants could achieve useful hydration using cosmetically acceptable materials.     

Facial skin mapping: from single point bio‐instrumental evaluation to continuous visualization of skin hydration,barrier function,skin surface pH,and sebum in different ethnic skin types

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.     

Skin smoothing effects of Dead Sea minerals: comparative profilometric evaluation of skin surface

The skin smoothing effects of three different liquid gels were compared on 20 mature women. Treatment applications were performed twice a day over a period of 4 weeks, and the skin roughness parameter (Rz) of all test participants was determined at the beginning and at the end of the study using a computer-aided laser profilometry, in accordance with DIN 4768 ff. At the end of the application period, the liquid gel with 1% of a Dead Sea mineral solution had an average skin roughness parameter reduction of 40.7%. The liquid gel without mineral additives showed an average reduction in skin roughness of 27.8%. The control gel without anti-wrinkle agents or the additives showed an average reduction of only 10.4%.     

Evolution of lipid composition in skin treated with blackcurrant seed oil

This report utilizes a new procedure based on epidermal stripping to analyse unlabelled skin fatty acids. This technique was applied to the study of human dry skin treated with blackcurrant seed oil, an essential fatty acid rich lipid also containing γ linolenic acid.
In human dry skin the usual fatty acids were found in the stratum corneum as in normal skin outer layers. Among the saturated series no significant difference was observed in the C16 chain but a smaller quantity of C18:0 was detected. In the unsaturated series a marked fall of linoleic acid as well as a higher level of C16:1 in the stratum corneum appeared as the major significant events that could characterize dry skin. γ linolenic acid was detectable neither in normal nor in dry skin. α linolenic acid was found but not consistently.
After multiple applications of blackcurrant seed oil in an emulsion preparation, impregnation of the stratum corneum was complete, and essential or other fatty acids contained in the oil (particularly linoleic and linolenic acids) were found in combination with endogenous lipids. Possibly they contribute to enhance the protective effect of the stratum corneum.