FDA analysis reveals sunscreen chemicals soak all the way into your bloodstream

Believe it or not, a safety testing on the active ingredients in sunscreen has never-before been conducted. This is because the chemicals were approved decades ago, before anyone thought they could be absorbed into the body. For this reason, the FDA led a small clinical trial on over-the-counter sunscreens.

The purpose was to test how the most common sun-filtering molecules behave after being sprayed on and rubbed in. The results were published in the journal JAMA. As it turns out, the UV-blocking chemicals seep directly into the bloodstream. This is contrary to what sunscreen manufacturers have been saying.

“Everyone had always thought that because these are intended to work on the surface of the skin that they wouldn’t be absorbed, but they are,” said Theresa Michele, director of the FDA’s division of nonprescription drug products and coauthor on the FDA-funded study.

For the trial, 24 volunteers were recruited — 12 men and 12 women. They were randomly assigned to apply one of four commercial available sunscreens: two sprays, a lotion, and a cream. As Wired reports, the participants applied the sunscreens according to the recommended labeling: four times a day for four days to 75 percent of their bodies (roughly the amount of skin showing if you wore a bathing suit).

Over the course of the four days, and for three days after, the researchers collected blood every few hours and analyzed it for the presence of avobenzone, oxybenzone, octocrylene, and ecamsule. In total, 30 samples were taken.

The team discovered that the photoprotective chemicals soak into the bloodstream within a few hours of being applied. This caused concentrations to rise above the FDA’s toxicology threshold that triggers further safety testing. In addition, the levels for three out of the four sunscreens remained elevated through the end of the study — three days after participants had stopped applying them to their bodies. The cream users saw their concentrations clear out the fastest.