A new study published in JAMArevealed that chemicals used in sunscreen can enter the bloodstream within a day. The study was conducted to determine whether the active ingredients in sunscreen needed to undergo a toxicology assessment. Researchers noted that FDA requires assessments for active ingredients with a systemic absorption greater than 0.5 ng/mL.

The study included 24 participants, who were randomized to one of four sunscreens. The sunscreen was applied to 75% of body surface area four times per day for four days, and blood samples were collected over the course of seven days. The sunscreens each contained one of the following four chemicals: avobenzone, oxybenzone, octocrylene, and ecamsule.

Systemic concentrations greater than 0.5 ng/mL were reached for all four products after four applications on day 1. The most common adverse event was a rash, which developed in one participant with each sunscreen.

CNN reportedthat experts from the American Academy of Dermatology and the Environmental Working Group are calling for continued use of sunscreen. That article notes that skin cancer is far more deadly.

That said, oxybenzone seems to be a good chemical to avoid: CNN cited studies showing potential links between oxybenzone and lower testosterone levels in adolescent boys, hormone changes in men, shorter pregnancies, and disrupted birth weights in babies, although causation has not been proven. And Hawaii, Palau, and Key West have all banned sunscreens containing oxybenzone because they cause coral bleaching.

AsWholeFoods previously reported, consumers are increasingly seeking out natural and organic sunscreens, and this latest study is likely to further drive that trend. Popular options include zinc dioxide and/or titanium dioxide, which are physical blockers, meaning they do not create a chemical reaction with the skin; they simply form a barrier that helps to keep UV rays from penetrating skin. Read more on natural options for summer skincare needshere.