Sunscreen use: controversies, challenges and regulatory aspects.

Mismatches between skin pigmentation and modern lifestyle continue to challenge our naked skin. One of our responses to these challenges is the development and use of sunscreens. The management of sunscreens has to balance their protective effect against erythema, photocarcinogenesis and photoageing owing to the potential toxicity of the ultraviolet (UV) filters for humans and the environment. The protection against UV radiation offered by sunscreens was recently standardized in the European Union (EU) based on international harmonization of measurement techniques. Four different categories of sun protection have been implemented along with recommendations on how to use sunscreen products in order to obtain the labelled protection. The UV filters in sunscreens have long been authorized for use by the EU authority on the basis of data from studies on acute toxicity, subchronic and chronic toxicity, reproductive toxicity, genotoxicity, photogenotoxicity, carcinogenicity, irritation, sensitization, phototoxicity and photosensitization as well as on environmental aspects. New challenges with respect to the safety of UV filters have arisen from the banning of animal experiments for the development of cosmetics. Future debates on sunscreens are likely to focus on nanoparticles and environmental issues, along with motivation campaigns to persuade consumers to protect their skin. However, more efficient sunscreen use will also continue to raise questions on the benefit in preventing vitamin D synthesis in the skin induced by sunlight.