A new study by the US Food and Drug Administration (FDA) suggests that chemicals in sunscreen leach into our blood at potentially unsafe levels. However, both the FDA and scientists are quick to warn that you shouldn’t throw out your sunscreen and face the Sun unprotected just yet.

Looking at spray, lotion, and cream sunscreens, researchers found that four chemicals – avobenzone, oxybenzone, octocrylene, and ecamsule – were present in the blood at surprisingly high levels after use. Levels, in fact, much higher than the FDA’s threshold for topical medications that must undergo safety tests.

"It's not like they went a little bit over," Dr Kanade Shinkai, a University of California, San Francisco dermatologist, said in a statement. "It's really quite high, orders of magnitude higher than that."

While the results seem a bit alarming, the study only involved 24 people in a lab-based setting. Therefore, absorption of these chemicals might be different in real-life settings where people are, for example, swimming in the sea or working outside.

Additionally, the sunscreens were tested “under maximal use conditions”, meaning they were applied four times a day for four days across three-quarters of each person’s body. Even with best intentions, many of us probably don’t apply sunscreen quite so rigorously, even though it’s recommended to maximize protection from the Sun.  

More research is needed to back up the findings and work out exactly what the health impacts of these chemicals are. Still, the danger posed by exposure to the Sun’s harmful UV rays likely far outweighs the potential risk that chemical sunscreens might pose.

Spending time in the sunshine without protection can lead to skin cancer, a disease that is on the rise. It predominantly affects those with light skin, but anyone can be affected. About 90 percent of non-melanoma skin cancers are linked to Sun exposure, so a generous helping of sunscreen can actually prevent the disease.

"I am concerned that people are going to stop wearing sunscreen," said Shinkai. "We know ultraviolet light from the sun has very deleterious effects on the skin. It causes photoaging. It causes sunburn. And, as such, it causes melanoma and [other] skin cancer."

The reason why the presence of sunscreen chemicals in the blood needs to be investigated further is that they might disrupt our hormones. The chemicals in question are known as chemical rings, which can enter our cells and form the key bases of many hormones. Animal studies have previously suggested that sunscreen chemicals might alter the body's delicate hormone balance somewhat.  

If you’re worried about using chemical sunscreens, mineral sunscreens make a good alternative that’s proven to be totally safe. However, the new study does not show that normal sunscreens are dangerous.

"The fact that an ingredient is absorbed through the skin and into the body does not mean the ingredient is unsafe," notes the FDA. "Rather, this finding calls for further testing to determine the safety of that ingredient for repeated use." 

“These results do not indicate that individuals should refrain from the use of sunscreen,” the study's authors conclude. Their findings are published in the Journal of the American Medical Association.