Os impactos da coloração sintética na integridade estrutural da fibra capilar

Abstract

Introduction: Hair coloring serves a multifunctional role, ranging from restoring youthfulness to expressing aesthetic and cultural identity. However, its use, especially with oxidative products, has been associated with structural damage to the hair fiber, such as protein and lipid loss, and increased porosity. In light of this, this narrative review aims to gather and analyze scientific evidence regarding the impacts of synthetic hair dyes on the integrity of the human hair fiber. Method: The search was conducted between April and June 2025 in the PubMed Central, Embase, SciELO, LILACS, and Web of Science databases, with defined inclusion and exclusion criteria. Results: Most studies investigated the effects of oxidative permanent dyes on different hair types. The main reported damages included cuticle destructuring, degradation of the superficial lipid layer, increased porosity, and loss of shine. Such effects result from repeated exposure to substances such as ammonia, hydrogen peroxide, paraphenylenediamine, and resorcinol. Strategies like the use of milder formulations, nanotechnology, and chelating agents showed potential to mitigate these damages. Nevertheless, there is a scarcity of standardized and long-term studies, especially considering ethnic and environmental diversity. Conclusion: Permanent dyes exert cumulative detrimental effects on the hair fiber. It is fundamental to promote the development of safer formulations and to guide consumers and professionals on the responsible use of these products. Future research should adopt multidisciplinary approaches, with greater methodological robustness, aiming at long-term hair health.