Purpose <p>This study aimed to prepare and characterize Diosmin-loaded nanostructured lipid carriers (Diosmin-NLCs) as a novel antioxidant formulation for topical drug delivery.</p> Methods <p>Diosmin-NLCs were prepared and characterized for particle size, zeta potential, stability, crystal properties, morphology, and encapsulation efficiency (EE %). Cytotoxicity, ROS level, and anti-tyrosinase activity of the optimized formulations were evaluated. Furthermore, in vitro drug loading capacity and the release profile of Diosmin-NLCs were investigated.</p> Results <p>The optimized Diosmin-NLCs formulation showed a particle size of 193.2 ± 4.5&#xa0;nm and a PDI of 0.27 ± 0.01. SEM showed that all nanoparticles were spherical, and the entrapment efficiency was above 80%. DSC thermogram indicated that Diosmin was loaded into the nanoparticles in an amorphous form. The drug release study for Diosmin-NLCs showed a continuous release pattern up to 48&#xa0;h, resulting in a rise in the cumulative amount of drug released from the Diosmin-NLCs. ROS test confirmed the antioxidant activity of Diosmin, and the NLCs formulations improved this effect. However, the cellular tyrosinase test did not show any antityrosinase effect of Diosmin. In vitro cytotoxicity assays confirmed the non-cytotoxic activity of Diosmin-NLCs and their safety for topical use. Stability studies showed no significant changes in particle size, EE%, and DL% over six months at all temperatures we examined (4^°C, 25^°C, and 37^°C).</p> Conclusion <p>In vitro experiments supported the potential of antioxidant and possibly anti-wrinkle activity of Diosmin as a topical formulation.</p>