Although research continues, no nanoparticle sunscreens are available in the United States. Two can be found in Europe. "One uses a 15% concentration of 50-nm zinc oxide and the other, a 5% concentration of 30-nm titanium dioxide," she noted
The Swedish government, however, has blocked 10 companies from marketing such sunscreens because of possible toxicity to aquatic flora, said Dr. Draelos. "These compounds can be toxic to organisms at the bottom of the food chain, including photo- and phytoplankton. The European Union countries have also said that labels must state whether the product contains nanoparticles."
The scientific jury is still out on how to make cosmetically acceptable sunscreens that offer optimal UVA protection while being physically and environmentally safe, Dr. Draelos said. "But we can’t ignore the opportunities they create for novel formulations."
Dr. Draelos disclosed financial relationships with numerous pharmaceutical companies.