Influence of Formulation, Application, and Environment on Sunscreen Effectiveness

This review provides a comprehensive analysis of the multiple factors influencing sunscreen efficacy, integrating studies published between 2016 and 2026. Beyond the type and concentration of UV filters, sunscreen performance is strongly affected by formulation design, photostability, environmental exposure, and user application practices. Formulation strategies involving emulsion systems, excipients, solubilization methods, and encapsulation technologies directly influence sun protection factor (SPF), cosmetic acceptability, and safety. Recent advances, including nanoparticle-based carriers, hybrid organic–inorganic systems, and antioxidant-enriched formulations, have shown potential to improve photostability, broaden UV protection, and reduce systemic absorption and environmental impact. However, inadequate application and insufficient reapplication remain major limitations to real-world photoprotection. In addition, differences in skin type, age, and lifestyle reinforce the need for more personalized sunscreen approaches. Growing concerns regarding the environmental effects of UV filters also highlight the importance of sustainable formulations and stricter regulatory policies. Overall, optimizing sunscreen efficacy requires not only technological innovation but also improved public education, transparent labeling, and user adherence. Future research should focus on multifunctional, eco-friendly, and user-centered sunscreens capable of providing effective and sustainable photoprotection.