Hydrogel facial mask for sensitive skin: A pilot study of long-term effects on hydration, barrier function and mechanical properties

Hydrogel-based facial masks are commonly used in skincare, yet their long-term effects in sensitive skin remain insufficiently characterized. In this study, we investigated the safety, tolerability and functional performance of a hydrogel facial mask based on poly(N-vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG-400) and agar, incorporating bioactive compounds (hyaluronic acid, ectoine, allantoin and tocopherol). The hydrogel was manufactured using radiation-induced crosslinking technology originally developed for medical applications and evaluated in individuals with sensitive and allergy-prone skin, with particular emphasis on hydration, skin barrier function and mechanical properties. The safety of the formulation was initially confirmed in a patch test (n = 30), followed by a 6-week open-label, baseline-controlled study (n = 15). Skin hydration, transepidermal water loss (TEWL), sebum level, mechanical properties, skin colour and pH were assessed using instrumental methods. Short-term dynamics after a single application were additionally evaluated, and the biological activity of the formulation was assessed in vitro using human dermal fibroblasts to quantify extracellular matrix (ECM) protein synthesis. Repeated application of the hydrogel mask resulted in progressive improvement in skin hydration and firmness, without measurable adverse effects on barrier-related parameters, sebum production, skin colour or pH. Short-term responses were transient and consistent with occlusion-driven modulation of the skin microenvironment, rather than sustained post-application effects. In vitro exposure to hydrogel-derived eluates induced a time-dependent increase in collagen and elastin synthesis, indicating biologically relevant cellular activity. The results indicate that the hydrogel formulation combines high tolerability with measurable functional efficacy through complementary physicochemical (hydration and occlusion) and biological (ECM-related) mechanisms, supporting its potential suitability for repeated use in the care of sensitive and allergy-prone skin.