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Sunscreen Chemicals Enter the Bloodstream

A recent study found that within hours of applying sunscreen, the chemicals in the sunscreen appear in the person's blood - and at levels high enough to be of concern. Of course the chemicals enter the body! Why is anyone surprised? Generally, assume that what you put or get on your skin enters your body - lotions, pesticides, etc.

The small study was conducted by the Center for Drug Evaluation and Research, which is a part of the US Food and Drug Administration (FDA). Commonly available sunscreens (2 different sprays, a lotion, and a cream) were applied on 24 volunteers according to directions. Within hours the four sunscreen ingredients being studied (avobenzone, oxybenzone, ecamsule and octocrylene) had entered the bloodstream at levels high enough to cause concern.  They also found that the blood concentration of three of the ingredients continued to rise as daily use continued and then remained in the body for at least 24 hours after sunscreen use ended.

The four chemicals studied are among a dozen chemicals that the FDA recently said needed to be researched by manufacturers before they could be considered "generally regarded as safe and effective." Especially worrisome is oxybenzone, which is in 85% of chemically based sunscreens - and has also been found in breast milk, amniotic fluid, urine, and blood. It is an endocrine disruptor, and linked to various health problems. With these chemicals, the more one uses, the more gets into the body - and people may apply sunscreen several times a day. They may also be found in personal care products and cosmetics. But unfortunately, as with so many chemicals that we are exposed to - long-term effects of frequent or chronic exposure are unknown.

The Environmental Working Group (EWG) rates sunscreen chemicals and is an excellent resource in finding safe sunscreens, as well as those that should be avoided. The EWG has a page discussing the problems with these chemicals, including that they are endocrine disruptors. They also have a page on nanoparticles (typically zinc and titanium dioxide), which are also used in sunscreens.ided. The EWG has a page discussing the problems with these chemicals, including that they are endocrine disruptors. They also have a page on nanoparticles (typically zinc and titanium dioxide), which are also used in sunscreens.

For years, you've been urged to slather on sunscreen before venturing outdoors. But new U.S. Food and Drug Administration data reveals chemicals in sunscreens are absorbed into the human body at levels high enough to raise concerns about potentially toxic effects.

Bloodstream levels of four sunscreen chemicals increased dramatically after test subjects applied spray, lotion and cream for four days as directed on the label, according to the report.

The levels far exceed the FDA-set threshold which require topical medications to undergo safety studies, said Dr. Kanade Shinkai, a dermatologist with the University of California, San Francisco School of Medicine. "It's not like they went a little bit over," she said. "It's really quite high, orders of magnitude higher than that."

Most sunscreens on the shelf use chemicals such as oxybenzone, avobenzone and octocrylene to block harmful rays. These organic chemicals absorb ultraviolet radiation and convert it into a small amount of heat.

However, animal studies have raised concerns that the chemicals, oxybenzone in particular, might disrupt normal hormone patterns in people, the FDA researchers noted in their study. "These molecules are chemical rings, essentially, and they absorb light," said Shinkai, who co-wrote an editorial accompanying the study. "Chemical rings are also the fundamental basis for a lot of hormones, and chemical rings tend to enter cells." Oxybenzone has been found in human breast milk, amniotic fluid, urine and blood, the FDA researchers said.

For its study, the FDA randomly had 24 adults apply either a sunscreen spray, lotion or cream four times a day for four days. The participants applied the sunscreen to three-quarters of their body surface. The study took place in a lab, and the agency drew 30 blood samples from each participant over a week to see whether the chemicals in the sunscreen got absorbed through the skin.

Levels of oxybenzone, avobenzone, octocrylene and ecamsule increased in the bloodstream after sunscreen use, researchers found.

The FDA has been tussling with sunscreen manufacturers over studies to test the safety of their products, said Shinkai. The agency has set a November 2019 deadline for manufacturers to provide safety data on their sunscreens, including evaluations of systemic absorption, the risk of cancer from the chemicals, and their effect on reproductive health, Shinkai said in her editorial.

The publication of this study might be intended to put pressure on the sunscreen industry to meet the deadline, she said. "The FDA is a regulatory agency. It's not a testing agency. For them to perform a research study is highly unusual," Shinkai said. "I think that's an important thing that suggests how concerned they were about this issue, and maybe perhaps the frustration on their part."

People who are concerned about the safety of chemical sunscreens can opt to use mineral sunscreens, Shinkai said. Those sunscreens rely on zinc oxide and titanium dioxide to reflect sunlight from the skin, rather than absorbing it like chemical sunscreens. "These we know are safe," Shinkai said of mineral sunscreens. "This is something that is evidence-based."

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