Researchers examined how two common sunscreen ingredients, avobenzone and oxybenzone, affect the protective outer layers of skin cells. They used laboratory models that mimicked the actual composition of skin cell membranes, which contain various fatty molecules including cholesterol and ceramides. The scientists tested how these sunscreen chemicals interacted with different combinations of these fatty substances, using specialized equipment to observe changes in molecular structure and arrangement. They discovered that avobenzone caused more disruption to the cell membrane organization than oxybenzone, though this effect depended on the concentration used. Interestingly, both chemicals showed a stronger preference for binding to certain fatty molecules like cholesterol, while they were less attracted to ceramides, which are naturally abundant in skin.
This suggests ceramides might actually provide some protection by blocking these chemicals from penetrating deeper into cells. When researchers examined actual skin cells under a microscope, they confirmed that both sunscreen ingredients did alter cell membranes. Overall, the study indicates that how these UV filters harm skin cells involves complex mechanisms, with damage to fatty membrane structures playing a significant role. (Source: Chem Phys Lipids, via PubMed.)
Source: PubMed — read the full article