The correlations shown between the skin biophysical parameters and environmental factors demonstrate that the skin biophysical parameters are affected by environmental factors.

No abstract

Background Despite the invention of various non-invasive bioengineering tools, skin-type analysis has largely been based on subjective assessments. However, advancements in the functional cosmetic industry and artificial intelligenceassisted dermatology are creating a greater demand for an objective skin-type classification system.Objectives To propose an objective skin-type classification system solely based on non-invasive, bioengineering devices; provide reference values applicable to the Korean population; and compare our reference values with those of published studies. Methods Biophysical parameter measurements were obtained from the 2018 International Skin Characteristics Data Bank Project conducted by the Foundation of Korea Cosmetic Industry Institute. The participants were 434 healthy South Korean adults. Each participant was assessed using eight bioengineering devices (Tewameter â , pH-meter â , Corneometer â , Sebumeter â , Cutometer â , Spectrophotometer â , PRIMOS â lite, and Janus â ). The measurements were divided into tertiles to determine reference points.Results Our objective skin-type classification consists of five main categories (sensitivity, hydration, oiliness, elasticity, and skin tone) and five corresponding subcategories (erythema, roughness, pores, wrinkles, and pigmentation, respectively). Each skin type was assigned based on the reference point of the biophysical parameter, which was established as the tertile value associated with 'unfavourable' skin characteristics. Individuals were categorized as having sensitive skin when the TEWL scores were over 18.0 g/m 2 /h or the pH was over 5.45; dehydrated skin when the corneometric value measured below 47.17 A.U.; oily skin when the sebumetric value exceeded 70 lg/cm 2 ; and loose skin when the cutometric R 2 value was below 0.68 E/mm. ConclusionsThis study is the first to provide a comprehensive skin-type classification system based solely on noninvasive biophysical parameters. As measurement data accumulate, the reference points will progress to become more accurate, and they will be subdivided according to gender, age, and ethnic group. Therefore, our classification system serves as a basis for artificial intelligence-based skin-type analysis.

This is the first study of the characterization and quantification of dermal papilla reflecting the dermal repair process after fractional photothermolysis through an RCM.

The effects of orally consumed probiotics on skin wrinkles and dryness are not fully known. A randomized, placebo-controlled, triple-blinded study was conducted with 148 healthy Korean female volunteers aged between 33 and 60 years, who were administered 1.75 × 109 colony-forming units (CFUs) of Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) (N = 74) or matching placebo (N = 74) for 12 weeks. Facial wrinkles (with 3-dimensional (3D) imaging), skin hydration, transepidermal water loss (TEWL), elasticity, and gloss were assessed at baseline and after every 4 weeks of the intervention. Questionnaire-based subjective evaluations of product efficacy and usability were also analyzed. The consumption of Bl-04 was safe and ameliorated significantly facial skin wrinkle parameters (total wrinkle area and volume, average depth of wrinkles, and arithmetic average roughness (Ra)) versus placebo at 4 weeks, but there were no differences at Week 8 or 12 between groups. Skin hydration, TEWL, elasticity, and gloss were similar between treatment groups, as were the subjective evaluation scores. Oral consumption of Bl-04 indicated promising short-term effects on skin appearance from the winter toward the spring. In future study designs, special attention should be paid to environmental conditions as well as to the skin condition and age of the participants.