New research from the U.S. Food and Drug Administration finds that more testing may be needed to prove four ingredients commonly found in North American sunscreens are safe.

The study published Monday in The Journal of the American Medical Association found avobenzone, oxybenzone, octocrylene and ecamsule were all absorbed into people’s bloodstreams above the limits normally required to waive toxicology testing in clinical trials.

The scientists involved say the evidence of absorption into the body shows more research is needed on the substances, although they do not recommend people stop using them.

David Andrews, a senior scientist and chemist with the non-profit Environmental Working Group, tells CTV News that the findings show the need for “additional commonsense safety testing.”

He noted that one of the ingredients, oxybenzone, was absorbed at particularly high levels and that concerns have previously been raised about its impact on the endocrine system and allergies.

The researchers noted that previous research has found oxybenzone in breast milk, amniotic fluid, urine and blood. Octocrylene has been observed in breast milk, they wrote.

“The FDA has been asking these sunscreen manufacturers to do (toxicology testing) for at least five years, if not longer, and they’ve really been dragging their feet,” Andrews said.

“We are supporting their call for greater testing to ensure these products are safe and effective for continued use,” he added.

Andrews said there are a number of options for sunscreens that don’t include these ingredients but instead contain zinc oxide or titanium dioxide.

The research involved collecting blood samples from 24 healthy volunteers who applied four different sunscreens four times per day for four days.

The researchers acknowledged a few limitations to the study, including the fact that the trial was conducted without the participants being exposed to outdoor heat, sunlight or humidity, which could impact the rate of absorption, and the fact that they didn’t examine differences related to formulations, skin types or ages.