We here at AGEIST are sunblock nerds. We have been fascinated by the substance for a long time, probably since we read that Australian skin cancer rates started to soar right about the time that "suntan lotion" became available. Interesting, right? The quick reason: UVB is what gives you a tan and a sunburn, and this is what is blocked by most chemical-based products. But it is UVA that is far more powerful and does most of the serious damage. UVA breaks down the blocking chemistry within most sunscreen, rendering it useless. If you really want to join the sunblock nerd world check out Environmental Working Group.
What do we use? That depends on what we are doing. Around town and for general use we like a mineral-based product that is more or less invisible on the skin like Avene 50, and if you have access to it, we like any of the Mexoryl-based products by La Roche or L’Oréal. If we are going to be out to get wet and sweat, we use Ombrelle 45 sport. If we are going for some ocean fun, surfing in the tropics, then we use Shiseido Sun Protection Stick Foundation, which is a trick we learned from the lifeguards on Waikiki.