Researchers emphasize, however, that people should not stop using sunscreen
The study, published Monday, was small — they conducted testing on just 24 people — but the results were concerning and significant enough to trigger further government testing. It was also one of the first studies to look into the effects of the chemicals in sunscreen.
The healthy, adult volunteers were split into four groups to test different kinds of sunscreen — a lotion, a cream and two types of spray sunscreens. Then, four times a day for four days, researchers applied 2 milligrams of sunscreen per square centimeter of skin on 75 percent of their body — the “recommended amounts,” though researchers said that the average person typically applies less.
The researchers took 30 blood samples from each volunteer during the seven total days of testing — all of which were spent indoors, out of the sun — and looked for four of the main chemicals in sunscreen: avobenzone, oxybenzone, octocrylene and ecamsule.
In just one day, all four chemicals were present in the volunteers’ blood, and exceeded 0.5 nanograms per milliliter, past the FDA guidelines.
However, researchers emphasize, people should not stop using sunscreen. In an editorial accompanying the study, both published in JAMA, Dr. Robert Califf, a former FDA commissioner, and Dr. Kanade Shinkai, a dermatologist at the University of California, San Francisco, wrote that more testing is needed.
“The demonstration of systemic absorption well above the FDA guideline does not mean these ingredients are unsafe,” they said. “However, the study findings raise many important questions about sunscreen and the process by which the sunscreen industry, clinicians, specialty organizations and regulatory agencies evaluate the benefits and risks of this topical OTC medication.”
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Califf and Shinkai also said that going without sunscreen is more dangerous.
“The findings of the study by Matta et al will likely raise concerns in the medical community, as well as among sunscreen users,” he said. “Until more information is available, it will be important to continue to reinforce clinical recommendations regarding the beneficial effects of photoprotection [sunscreen] for skin cancer prevention … avoidance of the sunscreen ingredients highlighted in this study, or of sunscreen altogether, could have significant negative health implications.”
If you’re concerned, opt for a natural sunscreen free of the four chemicals.