A critical review investigating the use of nanoparticles in cosmetic skin products

Abstract

The 1 to 100 nm nanoscale is a scale at which chemical reactions and biomolecular interactions can occur; the human skin is no exception. Regarding dermal exposure, engineered nanoparticles are used in numerous cosmetic formulations such as sunscreen, cleansers, creams, lotions, and makeup products. Their ability to improve ultraviolet protection, pigmentation, moisturization, and promote skin repair, and skin retention is appreciated. On the skin, nanomaterials first encounter resident bacteria and small molecules, i.e., the microbiome, and later interact with the superficial skin cells. The interaction of nanomaterials with the skin is complex because of their different compositions, reactivity, and scale. Physical and chemical features, composition, persistence in the environment, and transport across media are all factors that will affect nanomaterials' potential toxicity on humans and the environment. This review article focuses on current cosmetic ingredients claiming a nano nature, the unique characteristics of nanomaterials and their behaviour on the skin, how they can be suitable for natural cosmetics and how they behave in the environment.