Swetter: “Broad spectrum” is the rating designed by the FDA to ensure that a sunscreen filters both lower-wavelength UVB and higher-wavelength UVA radiation. That term can now only be used if UVA protection reaches a critical wavelength of 370 nanometers. That’s a problematic number since the UVA spectrum extends all the way to 400 nanometers. Unfortunately, no sunscreens commercially available in the United States (except for 25 percent zinc oxide, which is totally opaque) provide “far UVA” protection. There are sunscreens available in Europe and Australia that include far more effective UVA-filtering ingredients, namely Tinosorb S and Tinosorb M. In fact, Australia and Europe have the most effective UV filters for sunscreen formulations, while the United States has the least. We have been waiting for a decade for the FDA to incorporate these more effective UV filters into sunscreens, but the process is stalled, despite the 2014 Sunscreen Innovation Act, which enabled quicker time frames for FDA reviews of sunscreen chemicals available outside of the United States.