LSCM is a nondestructive method utilized to estimate particle size and distribution in sunscreens but cannot determine exact NP sizes [12]. LSCM images of untreated commercial sunscreens COM 1–6 were compared with those of the ZnO NP standard solution (Fig. 3). Sunscreen samples exhibited larger particles than the control solution. In addition, COM 1, COM 2, and COM 5 presented a more even particle dispersion compared with COM 6. LSCM images showed differences in optical contrast between organic residues and inorganic particles present in the sunscreens. LSCM provided insight on the aggregation and dispersion of primary particles but did not differentiate individual NPs because of the limited resolution of optical microscopy (200 nm). In addition, the low contrast of the sunscreen components may limit their resolution because the image contrast was based on different refractive indices [12]. Therefore, LSCM is not appropriate for particle size determination in cosmetic products.