A new study by the U.S. Food and Drug Administration (FDA) has confirmed that six active ingredients found in sunscreen products can be detected from a user’s blood with just one use, a follow-up to a pilot study released last year. But experts unrelated to the new study say people continue to use sunscreen because there is no evidence that the findings suggest a negative impact on health.
Last year, the FDA published the results of a small pilot study that found that regular use of several common sunscreens can lead to the detection of four key sunscreen chemicals in the blood: avobenzone, oxybenzone, Octocrylene and ecamsule. At the time, the preliminary study was criticized for its small sample size and the high level of application of the test. The follow-up study expanded the sample size, tested a variety of active ingredients, and studied blood absorption with only one sunscreen.
The new study confirms the results of the first study, finding that six major active chemical components can be detected in blood samples after a single application. All six chemicals (avobenz, oxybenzone, Okolin, homosalate), salicylic acid (octisalate) and gininoxate were found to have concentrations greater than 0.5 ng / mL.
The 0.5 ng / mL threshold mentioned in the study was not determined because of inherent insecurity, but FDA researchers point to the reason for choosing that particular threshold: it was chosen because the risk of cancer from any unknown chemical was less than one in 100,000 below that dose.
While these results are indeed worrying, experts strongly recommend that the public continue to use sunscreen if necessary, as it is fully recognized that UV exposure can cause cancer. The new study did not analyze this, or even assume that observed blood absorption levels may have any health effects.
Rob Chilcot, a toxicologist at the University of Hertfordshire, said the findings of the study were somewhat predictable because the skin was known to be not a solid barrier and could absorb chemicals from the surface. “This does not mean that the use of sunscreen products is unsafe, but that manufacturers need to have proper safety testing,” said Chilcott, who was not involved in the FDA study. “It should be emphasized that the use of sunscreen is good for your health and far outweighs the risk of not protecting your skin from excessive sun exposure. “
Antony Young of King’s College London echoed these views and confirmed that there was no clear evidence that the use of sunscreen had a negative mortality effect, but that there was clear evidence that UV exposure was dangerous. “Overall, there is growing evidence that sunscreen applied to the skin enters the circulatory system,” Young said in the new study. “The problem is that we don’t know what effect this has on health. From limited data, there is no evidence that long-term use of sunscreen has any effect on mortality. If used correctly, sunscreen is an excellent way to prevent short- and long-term adverse effects of solar UV radiation. There is no reason to change this. “
“…… Should clinicians continue to recommend the use of chemical sunscreen? Adewole Adamson, co-author of the new study, asked. “This is a pragmatic issue that affects the daily care of many people and is a critical clinical issue. In making an informed decision, clinicians must determine whether the benefits outweigh the potential risk of harm in a particular individual. Importantly, this balance may vary, depending on the characteristics of the sunscreen user (for example, for darker individuals and children) and may depend on the frequency and duration of use (e.g., daily use of vs intermittentuse; starting from infancy). “
Ultimately, it is not clear whether the blood absorption of these sunscreens is harmful to humans. Safety studies are not yet complete, and researchers believe chemical sunscreens should still form part of a broader UV safety program that also includes wearing protective clothing and simply avoiding intense sun exposure.
The new study is published in the Journal of the American Medical Association.