Innovative Anti-Ageing Cream with Hyaluronic Acid and Silk Proteins: Formulation, Safety and Skin Tolerance Assessment

The increasing demand for advanced cosmetic formulations based on natural biopolymers has stimulated the design of multifunctional and sustainable skin care products. Hyaluronic acid (HA) and silk proteins are widely recognized for their hydrating, barrier-supportive, and biocompatible properties. This study aimed to develop a novel topical formulation, integrating low- and medium molecular weight hyaluronic acid (LMW-HA and MMW-HA), encapsulated sodium hyaluronate (NaHA), silk, and hydrolyzed silk as active components, aiming to enhance skin barrier function and biocompatibility. The formulation was subjected to comprehensive physicochemical characterization including evaluation of appearance, odor, color, pH, viscosity, and stability, all assessed over 30 days and microbiological stability testing under controlled storage conditions. Safety evaluation followed a dual-phase strategy: (i) in silico toxicological screening of individual ingredients, including sensitization, and mutagenicity predictions, and (ii) in vivo skin compatibility assessment in 25 human volunteers using a semi-occlusive patch test. The formulation demonstrated good physicochemical stability, as pH remained stable, and viscosity showed no significant changes, confirming structural integrity, indicating preserved structural and microbiological stability throughout the study period. The in silico assessment indicated no mutagenic and/or sensitizing alerts and favorable safety margins for all components, confirming the safety profile of each ingredient, supporting their suitability for dermocosmetic use, while in vivo evaluation revealed no significant adverse effects, with irritation scores indicating no skin reaction (erythema or edema) across the test population. These findings support the potential of this novel biopolymer-based formulation as a safe and well-tolerated dermocosmetic product, aligning with principles of sustainable development and biomimetic design.