Photoprotectors and photoprotection

Photoprotection is a fundamental public health strategy to prevent sunburn, photoaging, actinic damage, and skin cancer, whose incidence is largely driven by ultraviolet (UV) radiation. Solar radiation includes UVA, UVB, visible light, and infrared; UVB is the main driver of DNA damage and carcinogenesis, while UVA contributes substantially to photoaging and melanoma risk. Effective photoprotection requires daily use of broad-spectrum sunscreens (UVA/UVB), applied at an adequate thickness (≈2 mg/cm²) and reapplied every 2–3 hours, complemented by behavioral measures such as seeking shade, wearing protective clothing, and avoiding peak sun hours. Sunscreens can be physical (zinc oxide, titanium dioxide) or chemical (e.g., benzophenones, octocrylene, octinoxate), each with advantages and limitations regarding cosmetic acceptability, skin tolerance, systemic absorption, and environmental impact. While chemical filters can be detected systemically and raise concerns about endocrine effects and marine toxicity, current evidence supports that the benefits of sunscreen use in preventing skin cancer clearly outweigh potential risks. Special populations—light phototypes, children, pregnant women, immunosuppressed patients, and individuals with photosensitive dermatoses or prior skin cancer—require stricter photoprotection (SPF 50+). Finally, sunscreen use does not preclude adequate vitamin D synthesis under real-world conditions, and supplementation is recommended only in high-risk groups practicing strict photoavoidance.