Physico-chemical properties of modern cosmetics for styling and their effect on hair structure

The article is dedicated to the physico-chemical properties of modern cosmetics for styling and their effect on hair structure under conditions of repeated thermal, chemical, and mechanical exposure. The relevance of the topic is determined by the growing use of multifunctional styling products that alter not only the visible state of the hair fiber but its interfacial chemistry, frictional behavior, porosity, and internal cohesion. The novelty lies in the interpretation of styling cosmetics not as isolated finishing products but as active systems of surface deposition, molecular penetration, and self-assembly acting within an already damaged biological substrate. The work describes the structural organization of the hair fiber, the transformation of its surface after degradation, and the operational mechanisms through which polymers, proteins, surfactants, and bioinspired ingredients modify fiber behavior. Special attention is paid to the interdependence between damage state, adsorption regime, and conditioning efficiency. The goal is to explain how modern styling formulations reshape hair structure at different functional levels. Analytical review and conceptual comparison of recent international studies were used. The conclusion outlines the transition from restorative claims to controlled structural compensation. The article will be useful for cosmetology researchers, formulation developers, and beauty practice specialists.