ZnO nanoparticles synthesized through Pogostemon cablin Benth (PCB) leaf extract demonstrate significant potential as active UV-protection agents in sunscreen cosmetic product. This research employs an environmentally sustainable approach by utilizing secondary metabolites present in PCB leaf extract, including flavonoids, alkaloids, and tannins compounds. These bioactive compounds function as natural bases sources and capping agents for hydrolysis process. The effect of adding PCB leaf extract concentration variations (5, 7, 9 %) has been studied on the results of ZnO nanoparticles bandgap values of 3.26, 3.17, and 3.12 eV, respectively. Morphological characteristics transformed from hexagonal wurtzite structures to spherical which is caused by the active role of functional groups in PCB leaf extract. The ZnO nanoparticles exhibited an average particle size distribution of 79.5 nm accompanied by exceptional homogeneity levels at −29 mV. For PCB leaf extract at 5, 7, and 9 % concentrations produced SPF values for ZnO nanoparticles measuring 19.33, 33.48, and 47.66, respectively. PCB leaf extract enables controlled ZnO nanoparticles size, enhanced UV absorption, and significantly improved for sun protection factor (SPF). © 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/