Chitosan application in cosmetics and dermatology - Antimicrobial and prebiotic potential to control human microbiome

The human microbiome has become a critically important field of study, with recent advances continuously revealing new aspects of its functional roles. A deeper understanding of the complex metabolic interactions between the microbiome, therapeutic agents, and the human host is now developing. A key challenge is the development of effective novel antimicrobial compounds, particularly those targeting biofilm-related infections implicated in a wide range of chronic diseases, to better control the human microbiota and treat typical skin diseases. Chitosan, a polysaccharide derived from various natural sources, possesses a unique set of biological properties, making it a promising base for numerous cosmetic and medicinal products aimed at managing dermatological diseases and modulating the microbiome. By altering its characteristics, chitosan's properties can be tuned to produce biomacromolecules with optimized activity beneficial to human microbiota. This review summarizes the sources and mechanisms underlying chitosan's antimicrobial activity, its immunomodulatory and anti-pathogenic effects, and critically evaluates its dual potential as both an antimicrobial and a prebiotic agent. Special emphasis is placed on chitosan-based formulations for treating skin diseases and promoting microbiome health - an emerging and promising area of research.