Nanosomes—lipid vesicles at the nanoscale—enable the encapsulation of both hydrophilic and lipophilic actives and are increasingly used as skin delivery systems in cosmetic products. Alongside nanoemulsions, polymer nanocapsules, and inorganic nanoparticles (e.g., TiO2, ZnO, Ag), they can enhance solubility, stability, residence time, and local bioavailability while enabling controlled release. This review summarizes nanocarrier structures, preparation concepts, and skin penetration pathways (transepidermal intercellular/transcellular and transappendageal), and discusses formulation factors that modulate delivery. We highlight applications in UV protection, anti-aging, and fragrance retention, focusing on lipid-based systems (liposomes/nanosomes, ethosomes, niosomes). Safety considerations are critically appraised with reference to EU and FDA frameworks, including physicochemical characterization, dermal penetration, irritation/sensitization, and genotoxicity testing. While most data indicate limited penetration through intact skin for particles ≥20 nm, enhanced uptake may occur under specific conditions (very small size, barrier impairment, mechanical stress), warranting careful risk assessment. We conclude with regulatory and sustainability perspectives and outline research priorities for long-term toxicology, in-use exposure, and standardization of methods.
Jadach et al. (Fri,) studied this question.