I apologize for not responding sooner to the wonderful feedback you have all provided on this issue about sunscreens. Unfortunately, the world of sunscreens has gotten more complicated then I ever could have imagined; nanoparticles, micronized actives, synthetic vs. mineral sunscreens, EU regulations versus US regulations or Britain versus Japan regulations, the vitamin D issue, and on and on. Add to that the fact that most synthetic sunscreens have estrogenic properties and there is almost no place to turn where there aren’t complications or controversy for using a sunscreen. I just finished writing the sunscreen section for the new edition of my book The Original Beauty Bible and have not yet updated my web site; I am in the process of doing that now.
 
Bottom line: The sunscreen issue is mind boggling. Here is what I have concluded from the work I’ve done and I will have the details up on my web site in May.

All synthetic sunscreens are more problematic for skin sensitivity and most, if not all, have estrogenic properties. Still, when a sunscreen includes avobenzone (butyl methoxydibenzoylmethane) stabilized by octocrylene (which is the primary way to stabilize avobenzone based on mounting research), Tinosorb, or Mexoryl SX (ecamsule) you will be getting impressive UVA protection.

Because of the way synthetic sunscreen ingredients work they increase free-radical damage in the epidermis and dermis which probably compromises the value of the increased UVA protection. However, choosing a sunscreen with synthetic active ingredients and a cocktail of antioxidants appears to mitigate this propensity for increased free-radical damage, thus allowing skin to better defend itself against sun exposure. Essentially, what happens in skin is that the antioxidants (assuming they’re in stable packaging) form a reservoir in the epidermis to help offset the oxidative damage the sunscreen actives cannot handle on their own (no sunscreen is capable of blocking 100% of UV light) or as a result of how they work to shield skin from sunlight (Sources: Journal of Photochemistry and Photobiology, April 2008, pages 24-34 and March 2006, pages 204-213; Molecules, August 2007, pages 1,845-1,858; and Journal of Cosmetic Science, November-December 2003, pages 589-598).

Mineral sunscreen ingredients (titanium dioxide or zinc oxide) are by far safer for most all skin types, though they are not without their own set of controversies. Both nanoparticled versions (under 100 nanometers) and micronized versions (over 100 nanometers) are typical in most all mineral SPF formulations. However, there is reduced UVA protection as a trade off for esthetics when you micronize or nanosize versions of these ingredients. That is why it’s important to apply liberally and reapply as needed (not to mention adding a foundation or pressed powder with sunscreen to your daily routine).

Now this is where my personal opinion and experience come into play: I think mineral sunscreens provide superior protection for many reasons but primarily because they are so benign and opaque (they cover skin well and are tenacious, almost like wrapping it in a security bandage). I know that the back of my hands and face don’t have “sun” spots because of my religious use of this blend of mineral sunscreen ingredients.
 
Synthetic sunscreens are absolutely an option and should not be avoided but in the world of sunscreens but there is no perfect solution. Suffice to say, the risk any combination of sunscreen actives may have is, without question, minor when it comes to the far greater risk of routinely exposing skin to sunlight without any protection from sunscreen.