It’s that time of the year again where regular application of sunscreen should become part of the daily routine; however, the U.S. Food and Drug Administration is warning that some active ingredients found in sunscreen can be absorbed into the bloodstream.
While regular sunscreen use is always recommended, the FDA says avobenzone, oxybenzone, octocrylene and ecamsule—active ingredients found in sunscreen—should undergo further toxicology testing.
Researchers from the FDA conducted a randomized clinical trial of 24 healthy volunteers to determine bloodstream concentrations of the four active ingredients in four sunscreens applied four times per day for four days with blood samples collected from study participants over seven days.
The results showed all four active ingredients were found in blood samples at levels exceeding the threshold recommended for toxicology testing.
The effect of these concentrations is unknown and further studies are needed to determine the clinical significance of these findings.
“Just because they are absorbed doesn’t mean they are unsafe,” said study coauthor Dr. Theresa Michele, director of the division of nonprescription drug products at the FDA in a statement to NBC. “That’s why we are asking for additional data.”
The clinical trial does have some limitations including the fact that it was conducted under indoor conditions without exposure to heat, sunlight or humidity, which may affect the rate of sunscreen absorption.
Also, the study wasn’t designed to look at differences in absorption by the type of sunscreen formulation, skin type or age of the user.
Researchers emphasize that the results don’t suggest people refrain from using sunscreen, which prevents skin damage from the sun.
“These products are used to prevent skin cancer,” Dr. Michele said. “It’s very important from a public health perspective that people use them, especially as skin cancer rates are increasing. Right now, we know that there are benefits from these products and we don’t know if there are any harms.”