BIOMEDICAL ANALYSIS OF COSMETIC FORMULATIONS AFFECTING EPIDERMAL REGENERATION LIPID BARRIER AND PH BALANCE

Abstract

A cosmetic formula is a complicated, multicomponent system that interacts with the epidermis and affects cell turnover, lipids organization, and skin surface acidity. It is known that the stratum corneum lipid matrix and pH physiological gradient control barrier function, water content, and resistance to environmental factors. In this research, a biomedical assessment of the impact of cosmetic formulations on epidermal regeneration, lipids barrier function, and pH balance in the adult face skin was conducted. 0.10% retinol and 5% niacinamide were applied alone and combined to reveal their effect on the skin. A prospective, randomized, controlled, parallel-group clinical trial was performed, and instrumental skin diagnostics such as TEWL probes, corneometric water content measurement devices, skin surface pH electrode, and dermal imaging were used along with biochemical analysis of stratum corneum proteins. Statistical analysis employed repeated-measures analysis of variance and paired comparison testing using SPSS, with significance set at p<0.05. Baseline and follow-up assessments were performed at predefined intervals during the 10-week treatment period to evaluate formulation-associated changes in biophysical and biochemical skin parameters. Results demonstrated measurable improvements in skin barrier and hydration. TEWL decreased from 14.6 to 8.5 g/m²/h, hydration increased from 37.9 to 60.3 AU, and surface pH decreased from 5.9 to 5.0. Epidermal thickness increased by 8.6 µm, indicating a pronounced treatment associated structural response with the combined formulation. These findings prove the effectiveness of properly developed cosmetic products in terms of the strengthening of the lipid barrier, regulation of pH levels, and renewal of the epidermis.