Background Nowadays, face masks are a crucial part of our daily life. Previous studies on their impact on the skin usually focused on the adverse effects of face masks. Few studies have assessed their influence on skin characteristics. In a previous study, we identified the short‐term effects of wearing face masks. Herein, we describe the long‐term skin effects of face masks, for a period of 6 months. Materials and methods Healthy volunteers (19 men and women), who wore face masks, participated in the study from June 2020 to December 2020. In all participants, skin characteristics such as trans‐epidermal water loss (TEWL), skin hydration, skin elasticity, skin pore area, skin keratin amount, skin temperature, skin redness, skin temperature, skin redness, and skin color were measured three times. Results TEWL, skin hydration, skin elasticity, skin pore area, skin keratin amount, and skin color changed significantly after 6 months. TEWL, skin hydration, skin pore area, skin keratin amount, and skin color were significantly different between the mask‐wearing and non‐mask‐wearing areas. Conclusion Long‐term daily use of face masks can alter skin characteristics. Special care should be focused on the mask‐wearing regions.

BackgroundBlue light from electronic devices enriched with a peak at 456 nm affects circadian rhythm and antioxidant balance of skin, necessitating the study of photoprotection against the 456‐nm blue light.AimsThis study aims to report that blue light (456 nm) can cause skin pigmentation and proposes a new clinical evaluation method for blue light (456 nm) protection based on the skin pigmentation level.Patients/MethodsWe developed a clinical device (ABC deviceTM) that emits blue light (peak = 456 nm). Based on the minimal persistent pigment darkening dose (MPPD) determined from visual evaluation and melanin index measurements, we proposed the “protection grade of blue light (PB)” guideline to assess the protective ability of skin against blue light.ResultsHuman skin irradiated with blue light (456 nm) showed a light dose‐dependent degree of pigmentation. The MPPD on unprotected and protected skin was 135 J/cm2 or 180 J/cm2 and 135‐225 J/cm2, respectively. The ABC device™ and the proposed clinical method were used to test the four blue light blocking assessments of TiO2. Consequently, the inorganic filter with TiO2 effectively blocked the blue light (456 nm). The AP product demonstrated the ability to block blue light by 1.15 times (PB = 1.15), which significantly lowered the melanin index of the skin after irradiation as compared to that of the unprotected skin (P < .001).ConclusionWe propose an objective clinical evaluation method for blue light protection. This study elucidates the properties of blue light blockers for customers suffering from blue light pollution.

Background Although changes in skin depend on the external environment, researchers have performed only a few studies on effect of the actual environment. Most studies have researched skin characterization based on changes in the humidity or temperature. Aim/objective This study aimed to evaluate changes in the skin based on the difference in indoor and outdoor temperatures and humidity during summer in South Korea and Southeast Asia. Methods Twenty‐two female participants aged 25–39 years were included. Skin hydration, sebum (cheek, forehead), colour, transparency and pores of the participants were measured after a 30‐min exposure to high temperature and high humidity (HTHH) environment and a 30‐min exposure to low temperature and low humidity (LTLH) environment. Subsequently, exposure to HTHH environment for 30 min +LTLH environment for 30 min was performed after a total of 1 h and repeated. Results Repeated exposure to HTHH and LTLH environments increased the skin's sebum content and haemoglobin index. Additionally, skin elasticity was significantly reduced, with patients in their 30 s showing greater changes than those in their 20 s. Conclusion Repeated differences in temperature and humidity cause skin ageing, loosen skin vessels and reduce skin elasticity, thereby leading to skin ageing.

Background Skin darkening because of increased and irregular synthesis of melanin causes melasma, solar lentigo, and freckles. Melasolv™, produced in the early 2000s, shows potent depigmenting effect and has low cytotoxicity. It has been used as a brightening agent in cosmetics for decades. Aims This study was conducted to investigate whether Melasolv™ is effective for the skin of ASEAN (Southeast Asia) women. Methods We recruited ASEAN women in Singapore and divided them into two groups (active group vs. placebo group). Melasolv™ and placebo formulations were applied twice a day for 12 weeks. The changes in the pigmented spots were visually evaluated by an expert and assessed using a spectrophotometer and Mexameter at 0, 4, 8, and 12 weeks. Results The visual evaluation revealed significant improvements, in both size and color intensity, in the active group compared with those in the placebo group at 12 weeks. In the spectrophotometric evaluation, the L* value of the pigmented spots in the active group was significantly higher than that in the placebo group at 12 weeks. Similar results were obtained in the evaluation using the Mexameter. After 12 weeks, the melanin index of the pigmented spots significantly decreased, and it was significantly higher than that in the placebo group. There was no significant change in the erythema index. In the image analysis, there were no significant differences in skin color brightness and evenness in the active group compared with those in the placebo group. Conclusion Melasolv™ can be effective used for skin brightening.

The skin is the outermost layer of the body and is exposed to various environmental conditions, and skin characteristics change along with the environmental conditions. Several studies evaluating variations in skin characteristics have attributed ultraviolet light and external humidity as the factors responsible for skin changes. Skin conditions vary considerably with drastic changes in humidity. Moisture in the skin decreases in an environment that changes from 70% humidity to 40% humidity. 1 There are also reports of a decrease in transepidermal water loss (TEWL) in those who work at low temperatures. 2 We are increasingly exposed to various environments, some of which have never existed before, such as fine dust, face cover/masks due to coronavirus disease (COVID-19) epidemic, and lack of sleep. It is worth noting that the number of studies related to sleep is increasing day by day. Some have reported changes in biophysical properties of skin, such as facial pore size, skin tone, skin hydration, elasticity, desquamation, translucency, and blood flow after constant sleep deprivation. 3 In addition, studies have shown that reduction of sleep from 8 to 4 h, even for 6 days, reduces elasticity and leads to skin aging. 4