Elsevier May 13 2025 The skin microbiome plays an important role in health and disease. Researchers have now substantiated that certain skin bacteria can protect us from the sun's ultraviolet (UV) radiation specifically by metabolizing cis -urocanic acid using an enzyme called urocanase. This enables the skin's ability to fine-tune how it responds to UV radiation The findings of the study in the Journal of Investigative Dermatology , published by Elsevier, provide a striking case study that