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Background: Sunscreen products aim to help protect the skin against UV radiation and consequently reduce the risk of early skin ageing and skin cancer. However, it is well known that some sunscreen ingredients are not photostable, but this usually refers to irradiation with UV light. Moreover, it has to be mentioned that a relative cumulative erythema effectiveness compliant light source is used for the in vivo sun protection factor (SPF) testing. Here, UV simulators equipped with a xenon arc lamp use filters such as WG320 and UG11 (thickness 1 mm) to minimize infrared (IR) radiation and wavelength below 300 nm. However, under practical conditions, the sunscreen product is not only exposed to UVA/B light, but also to visible light (VIS) and IR light. In fact, the spectrum of solar radiation is composed of approximately 7% UV, 39% VIS and 54% IR. Aims: To investigate the influence of short-wave and long-wave radiation on the photostability of sunscreens. Methods: Irradiation was performed with the Suntest CPS+ that is considered to closely imitate solar radiation. The filter UG11 (thickness 1 mm), which absorbs much of the VIS and IR light, and the glass filter WG320 (thickness 2 mm), which effectively absorbs radiation of wavelengths less than 300 nm, were used in the Suntest CPS+ both individually and in combination and were inserted between the light source and the samples. The following transmission measurements were carried out with Labsphere's UV-2000s device. Here, the effectiveness (percentage change of SPF before irradiation to SPF after irradiation) as a measure of the photostability was calculated. Results:As expected after total solar spectrum irradiation, the effectiveness in all tested sunscreens is lower compared to relative cumulative erythema effectiveness light used for in vitro testing of SPF. In the reference sunscreen formula S2 as well as in the two different sunscreen products, especially long-wave radiation (>400 nm) had an effect on photostability, whereas short-wave radiation had only a minor impact. In contrast, in the BASF sun care gel line only short-wave radiation below 300 nm had an effect on photostability, and blocking VIS and IR light had no effect at all. Conclusion:Based on these data, we can conclude that short waves and/or VIS + IR light have an influence on the photostability of sunscreens. [ABSTRACT FROM AUTHOR]

Background: About 50% of the sun's radiation arriving on earth is visible light (VIS). For a long time, its effects on human health have not been fully investigated. But recently, the influence of VIS has gained more attention, especially regarding skin physiology. Studies showed various effects, many of them harmful, comparable to UV radiation. As a result, there are now a few sunscreens commercially available which claim protection against VIS. The question of whether protection is necessary is still much discussed. Aims: The objective of this study was to develop an easy-to-perform high-energy visible (HEV) and low-end visible (LEV) light transmittance method to determine the direct VIS protection of sunscreens and other cosmetic samples. Furthermore, the influence of the brightness of the tested products on the HEV, LEV, and infrared A protection was investigated. Methods: An experimental setup consisting of a light source, a VIS-transmissible filter system, and a sensor unit was built to measure the direct VIS protection of sunscreens and other daily skin care products in two ranges of the VIS area. For a closer look, the brightness of the samples was evaluated by photometric assessment. Results/Conclusion: The experimental setup could be validated. It could be demonstrated for the first time that there is a strong positive linear correlation between transmittance and brightness of tinted sunscreen and daily skin care products with sunscreen properties in the HEV, LEV, and infrared A range. However, tinted samples worked best in the blue light region, and the higher the wavelength range, the lower the protection. [ABSTRACT FROM AUTHOR]

Background: Skin reaction to spaceflight has not really been studied yet, although the skin has a very important barrier function to protect the body and can contribute to a more general understanding of physiology. It is proposed here to make a more thorough investigation of the skin during long-term spaceflight, using noninvasive techniques. Aims: The aim of the present Skin-B study is to investigate the kinetics and range of possible skin modifications during long-duration spaceflights and their recovery. Methods: In order to investigate the effect on skin physiological parameters during spaceflight, measurements were carried out on 6 astronauts with respect to skin hydration, transepidermal water loss/barrier function, and surface evaluation of the living skin in orbit. Additional measured parameters on the ground were skin elasticity, skin density and thickness, as well as microcirculation. Results: Data from the Skin-B subjects (n = 6) contradict the results obtained in the previous pilot study SkinCare (n = 1 subject). In the present study, no deterioration of the skin was found but rather an improvement in skin hydration and skin barrier function, and no changes or improvement in the appearance of the skin surface. Furthermore, the skin density and skin thickness as well as skin elasticity values were unchanged from pre-flight values. Conclusion: In conclusion, we found that spaceflight under present conditions has no negative impact on skin physiological parameters. [ABSTRACT FROM AUTHOR]

Background: One of the most challenging and important factors of manned space missions is to keep astronauts healthy on orbit. In a study on 46 ISS crew members who were on 6-month (average) missions, skin rashes were the most self-reported event. Furthermore, among notable events, 40% were classified as skin rashes/hypersensitivities. Thus, especially skin conditions during space travel are of major clinical interest and require further research. Aims: The aim of the study was to determine skin conditions in space flight among US and European astronauts, especially taking into account the terrestrial skin conditions as well as on-orbit skin care habits. Methods: A preflight questionnaire was given to the astronauts asking about their terrestrial skin care habits and skin conditions/atopy before launch. In addition, they were asked to fill out a postflight questionnaire asking about their on-orbit skin care routine and whether any special observations regarding the skin were made during flight. Results: A total of 23 skin symptoms were recorded by 8 nonatopic astronauts (mean age: 41 years) during the mission. The symptoms were peeling (21.74%), rash (17.39%), dryness (13.04%), severe dryness (8.70%), reddening (8.70%), itchiness (8.70%), bruising (4.35%), skin sensitivity (4.34%), bumps (4.35%), acne (4.35%) and slow healing of contusions and lacerations (4.35%). Especially the hands and feet were affected by skin problems. As a result of this examination, it was shown that the skin symptoms correlate with poor hygiene on orbit, whereas the factor "environment" on the ISS plays a minor role. Surprisingly, 2 astronauts even experienced positive effects on their skin. Conclusion: Based on these preliminary data, it is important to pay more attention to skin hygiene and maintenance in space. [ABSTRACT FROM AUTHOR]

Background: Today, the sun protection factor (SPF) value of sunscreen products is determined in vivo with a standardized protocol (EN ISO 24444: 2010), and the measured SPF biological end point is the visible skin erythema. However, many of the sunscreen products currently available on the market have antiphlogistic ingredients, which may potentially result in an overestimated SPF of the sunscreen. Aims: To investigate the potential influence of the antiphlogistic ingredients panthenol and bisabolol in sunscreens on the determined SPF value in vivo. Methods: Formulations with different concentrations of the antiphlogistic ingredients bisabolol or panthenol were tested. As a reference, a base formulation (vehicle) without antiphlogistic ingredients was used. First, the SPF of the sunscreen formulas with and without antiphlogistic ingredients was analyzed in vitro. To investigate whether the antiphlogistic ingredient may suppress the inflammatory response to ultraviolet (UV) irradiation, the SPF was determined in vivo. Finally, selected formulations were also analyzed in an erythema model for testing formulations on UV-induced inflammation. Results: It could be confirmed that no differences between the formula with and that without the active antiphlogistic ingredients bisabolol or panthenol exist when measured in vitro. However, there was also no statistically significant difference in the erythemal response between the vehicle (without an antiphlogistic active ingredient) and the test formulations with different concentrations of the antiphlogistic active ingredients in the in vivo determination of the SPF. Evidence of anti-inflammatory activity of the sunscreen antiphlogistics bisabolol and panthenol was also not apparent in the UV model over a time course of 48 h. Conlusion: The antiphlogistic ingredients panthenol and bisabolol incorporated in the tested sunscreen formula do not interfere with erythema reddening and thus do not affect the SPF value in vivo. [ABSTRACT FROM AUTHOR]

Background: Every day human skin is exposed to infrared A (IRA) radiation as part of the natural sun rays. As IRA radiation accounts for around one third of the solar radiation, it has gained great attention concerning its effects on the human body and skin. In the past few years it has been discussed controversially whether IRA radiation (of solar origin) is harmful or not. Nonetheless, there are several sunscreens on the German market that claim IRA protection for themselves. Aims: The present study seeks to find an experimental set-up and a test procedure for the determination and quantification of direct IRA protection (realized via reflection or absorption of the IRA radiation), since to our knowledge these do not yet exist. Methods: In this study we proved the usability of a set-up consisting of a light source, an IRA-transmissible filter system and a sensor unit, for the determination and quantification of the IRA protection of cosmetic and non-cosmetic samples. Results/Conclusion: The applicability of the IRA emission of the light source, the spectral detector, transmissivity of the filter systems and the sample carriers could be validated. This experimental set-up can be used as an in vitro test procedure for the determination of direct IRA protection. [ABSTRACT FROM AUTHOR]