There are two types of UV rays you need to be concerned about when buying sunscreen:  UVA and UVB.  UVB are the burning rays, and SPF ratings only measure a sunscreen’s effectiveness against UVB rays.  In the last decade or so, UVA rays have been shown to be responsible for aging: wrinkles, skin cancer, DNA mutation.  Sunscreens label themselves Broad Spectrum when they are effective against both rays, but the effectiveness of the UVA protection is hard to know.  In the US, the most effective UVA sunscreens are those that contain a physical sunblock (like titanium dioxide, that actually block the rays with a physical barrier), and the chemical sunblock Avobenzone, sometimes marketed as Parsol 1789.  But neither is as effective as Mexoryl, which has been available in Europe and Canada for years.  Mexoryl is the most effective chemical UVA block, and doesn’t lose its effectiveness as quickly as Avobenzone in the sun.  On Monday, L’Oreal got FDA approval to sell Mexoryl-based sunscreen in the US.  But you don’t have to wait until fall to get it.  A quick Google or eBay search will turn up Anthelios sunscreen available from foreign sellers.  I bought mine from a Spain-based seller FashionEyeStore whose prices, including  FedEx shipping, were cheaper than most of the Canadian pharmacies that sell the products online.  The Anthelios XL Fluide Extreme is the most lightweight of the products, though I still found it a little greasy, and it is not waterproof or sweat-resistant.  The Children’s version is water-resistant, but still ran in my eyes.  I’m sticking with the suncreens I wrote about earlier, but if you’re particularly concerned about UVA rays, and sweat/water resistance isn’t an issue for you, Anthelios is the best protection you can buy.