Trehalose in an Emulsion-Based Carrier: Effects on Skin Hydration and Transepidermal Water Loss

Dry skin and skin barrier dysfunction are common dermatological problems associated with increased transepidermal water loss (TEWL) and reduced stratum corneum hydration. Among moisturizing agents, trehalose—a naturally occurring disaccharide—has attracted considerable attention due to its moisturizing, protective, and stabilizing properties. The aim of this study was to develop dermatological emulsions with desirable physicochemical, rheological, mechanical, adhesive, and moisturizing properties for dry skin care. Six placebo emulsions, differing in emulsifier and oil compositions, were prepared and evaluated for stability, pH, viscosity, rheological behavior, texture, adhesion, and spreadability. Based on the results obtained, the formulation containing avocado oil and Olivem 1000 was selected as the optimal base for incorporating trehalose at concentrations of 1%, 2.5%, and 5%. The formulations were further evaluated in vivo using TEWL and corneometry measurements. All emulsions exhibited non-Newtonian shear-thinning and thixotropic properties. Regular application of the emulsions reduced TEWL by approximately 33%, while skin hydration increased up to 102%. However, discontinuation of the emulsion application resulted in decreased skin hydration and increased TEWL, suggesting the need for constant use.