- FDA investigators tested six of the main active ingredients in sunscreen lotions and sprays
- All of the chemicals had concentrations in the blood above the FDA threshold of 0.5 nanograms (ng) per milliliter (mL) of blood plasma
- Each ingredient was above the threshold seven days after sunscreen was applied and two were above the threshold 21 days after application
- One chemical at its highest level was 180.1 ng/mL, which is 360 times above the threshold
A new study tested six of the main active ingredients in sunscreen lotions and sprays and found they had had higher concentrations in the blood than the FDA’s threshold (file image)
We might be absorbing more sunscreen chemicals into our bloodstream than is safely recommended, federal health officials say.
Investigators from the US Food and Drug Administration (FDA) tested six of the main active ingredients in sunscreen lotions and sprays.
They found that all of the chemicals had higher concentrations in the blood than the FDA’s threshold.
One of the ingredients had a concentration that was 360 times greater than what is recommended by the agency.
The FDA and American Academy of Dermatology stresses the chemicals are safe but several reports have linked them to hormone disruption and liver and kidney failure.
The team stresses that the findings don’t mean the public should stop using sunblock, but that more research is needed to determine the effect of these levels in the blood.
Sunscreens usually contain one or several of these six chemical ingredients: avobenzone, oxybenzone, octocrylene, homosalate, octisalate and octinoxate.
The ingredients have come under scrutiny in recent years due to questions surrounding their safety.
In 2012, the Environmental Working Group released a report recommending that sunscreens be free of oxybenzone due to potential links to cell damage that may lead to skin cancer.
And a 2017 study found that octocrylene caused DNA damage in various aquatic animals.
Another study conducted the same year found that avobenzone can turn toxic when exposed to chlorine and potentially lead to kidney and liver dysfunction.
For the new study, published in the Journal of the American Medical Association, the team recruited 48 volunteers for a period of 21 days.
They were given one of four commercially available sunscreens and told to apply it once on day one and four times a day on days two through four.
Blood samples were collected multiple times across the 21-day period.
Researchers found that all of the chemicals had concentrations greater than 0.5 nanograms (ng) per millimeter (mL) of blood plasma, which is the FDA’s threshold.
All of the ingredients remained above the threshold at day seven, and plasma levels of homosalate and oxybenzone continued to remain above the threshold on day 21.
The highest number seen was the plasma concentration for oxybenzone on day four, which was 180.1 ng/mL after some participants used an aerosol spray with the ingredient.
That’s 360 times greater than the FDA threshold.
The researchers emphasize that people should keep using sunscreen, but that more safety studies are needed by the FDA.
In a linked editorial, Dr Adewole Adamson of Dell Medical School at The University of Texas at Austin and Dr Kanade Shinaki of the University of California, San Francisco stressed the importance of continuing to wear sunscreen to protect against UV radiation and skin cancer.
‘The report…provides important information on the systemic absorption of chemical sunscreen filters that deserve attention, discussion, and additional study to understand their clinical relevance,’ they wrote.
‘Because good evidence indicates that UV exposure is a key modifiable cause of skin cancer and melanoma, sunscreen should continue to be an essential part of UV safety.’