What you apply to your skin absorbs into it and can get into your bloodstream. A recent study by the FDA reported that four chemicals used in sunscreens (oxybenzone, avobenzone, octocrylene, and ecamsule) exceeded acceptable limits for chemicals absorbed into the blood, which warrants further studies of their safety. The FDA has also reported that it has adequate safety data on only zinc oxide and titanium dioxide, which are mineral sunscreens.
Chemical sunscreen ingredients are still a big question mark. These chemicals were found in breast milk. And they may negatively affect hormone levels in women and men creating other adverse health effects.
Another issue with conventional sunscreen ingredients is that they contain known skin irritants. And several have been banned in Hawaii because even diluted in seawater, they have been shown to kill coral.
So we recommend playing it safe, use nontoxic, mineral-only sunscreens. If you’re ever unsure of the ingredients in your sunscreen, check the Environmental Working Group’s Skin Deep database, which gives safety information on a wide range of products and ingredients.