• Kevin Elliott

Your sunscreen: alert on chemicals inside

Skin cancer affects more than three million people in the United States each year, with a rate of 22.7 per 100,000 people in Oakland County, Michigan. While sunscreen is key to protection from the sun's harmful ultraviolet rays, new research on sunscreen ingredients has numerous consumers and advocacy groups concerned that some products may be affecting health and the environment.

Slathering on a layer of sunscreen for a day outside has been normal operating procedure for sun worshippers and responsible parents for the last several decades, and the advent of lighter and more effective sunscreens has increased the number of products available to consumers, as well as their use. However, recent testing has shown that many of the most popular sunscreens on the market contain ingredients that are absorbed by the skin and enter the bloodstream.

In May, researchers with the U.S. Food and Drug Administration (FDA) presented its own data showing that four of the most widely used sunscreen ingredients do in fact enter the bloodstream through absorption into the skin.

The tests follow a proposed rule introduced by the FDA in February of this year that would update its sunscreen rulebook, including active ingredient safety, dosage forms, sun protection factor (SPF) ratings and broad-spectrum requirements. At the heart of the proposed rule is the FDA's longstanding goal to gather additional safety data, including studies to determine whether ingredients that penetrate the skin can cause endocrine disruption, cancer or other harms.

Whether or not the tested sunscreen ingredients have negative impacts on human health isn't yet known with certainty. However, there is evidence that some sunscreen ingredients that are taken up by humans may be responsible for a loss of coral reef habitats. Additional research suggests those same ingredients may act as endocrine disruptors on some aquatic life. Environmental concerns alone have led to bans on the sale of some sunscreens in all or part of two states.

Weighing in on the issue has been the consumer advocacy organization Environmental Working Group (EWG), which has mounted its own campaign raising concerns about sunscreen ingredients, as well as releasing its own guide to sunscreens.

According to the EWG, many studies in animals and cells have shown sunscreen ingredients to affect reproduction and thyroid hormones. Further, the group claims some sunscreen additives may speed the development of skin cancer, and questions the overall effectiveness of sunscreen in light of potential risks.

With the FDA's final rule not expected to be complete before the end of this year, health experts are urging consumers to continue their current use of sunscreens as a measure against skin cancer, sunburn and other harmful effects caused by the sun.

Associate Professor and Assistant Chair for Medical Education with the University of Michigan's Department of Dermatology Frank Wang said sunscreen use is vital to lowering the risk of skin cancer.

"I couldn't agree more," he said regarding the continued use of sunscreen. "We are seeing an epidemic of skin cancer, including more deadly forms, like melanoma, in younger individuals. And it's one of the most preventable cancers. There are no doubt benefits from sunscreens."

In terms of risks associated with absorption of sunscreens, Wang said more research needs to be done. However, he said the known benefits of sunscreen outweigh the known risks – at least at this time.

"I still recommend sunscreen until more is known," he said. "I usually tell patients that (sunscreen) is just one part of their sun protection regimen. Staying out of the sun in the middle of the day, wearing sun protective clothing, hats and glasses all should be done in combination of sunscreen.

"If you personally have some concerns, stick with something that we know is safe, like physical sunscreens like zinc oxide or titanium dioxide."

Both zinc oxide and titanium dioxide have been characterized as Generally Recognized as Safe and Effective (GRASE) in the FDA's proposed rule. The two ingredients are considered mineral or physical sunscreens. Mineral sunscreens sit on top of the skin and provide protection from the sun by reflecting rays away from the user. Chemical sunscreens, however, work by being absorbed into the skin and creating a chemical reaction with ultraviolet rays, converting the rays into heat and then releasing that heat from the skin.

The FDA also proposes listing two specific chemical sunscreen ingredients as not GRASE, or not considered safe for use: PABA and trolamine salicylate — which aren't currently marketed in products for sale in the United States.

Another dozen chemical UV-filters already widely used in the United States are now under consideration by the FDA, which said there is insufficient evidence to determine whether the ingredients are GRASE, or safe for use. Those ingredients include: cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone and avobenzone. Four of those chemicals – avobenzone, oxybenzone, octocrylene and ecamsule – were found by FDA researchers in May to enter the bloodstream through the skin.

"The FDA has been working on sunscreen for a very long time, and the science and use of sunscreen have been evolving," said Theresa Michele, director of the FDA's Non-prescription Drug Products. "Sunscreen is regulated in the FDA's OTC monograph, which is like a rulebook. If manufacturers follow the rulebook, they can bring products to market with FDA approval. That started back in the 1970s, when people didn't use sunscreen very much. Then science evolved and we started learning more about UV radiation and the damaging effects on the skin, and we realized sun protection is critical to prevent cancer and premature aging."

Drawing on the FDA's study that found some of the ingredients are absorbed into the skin, the FDA is requiring additional information from manufacturers to determine safety and effectiveness.

"For example, the available literature includes studies indicating oxybenzone is absorbed through the skin to a greater extent than previously understood and can lead to significant systematic exposure, as well as data showing the presence of oxybenzone in human breast milk, amniotic fluid, urine and blood plasma," the FDA said in its proposed rule. "The significant systemic availability of oxybenzone, coupled with a lack of data evaluating its full absorption potential is a concern, among other reasons, because of questions raised in the published literature regarding the potential for endocrine activity in connection with systemic oxybenzone exposure. Nearly all of these sunscreen active ingredients also have limited or no data characterizing their absorption."

In addition to evaluating sunscreen ingredients for safety, the FDA's proposed rule would consider sunscreen dosages in spray, oils, lotions, creams, gels, butters, pastes, ointments and sticks as GRASE. Powder forms are being considered, but additional data is requested. However, wipes, towelettes, body washes, shampoos and other dosage forms are proposed to be new drugs because the FDA hasn't received data showing they are eligible to be included in the monograph.

The proposed rules would also cap the maximum SPF value on labels at SPF 60+, and to require sunscreens with an SPF higher than 15 to also provide broad spectrum protection. Additionally, for broad spectrum products, as SPF increases, the magnitude of protection against UVA radiation also increases. "Broad spectrum" protection refers to protection against both UVA and UVB rays, as all sunscreen products don't automatically protect against both.

The proposed rule would also require new product label requirements to assist consumers to more easily identify key information, including the addition of active ingredients on the front label; a notification alert for sunscreens that don't prevent skin cancer, and revised formats for SPF, broad spectrum and water statements.

Finally, the proposed rule would consider all products that combine sunscreen with insect repellents as not generally recommended as safe and effective.

"This proposed rule is quite comprehensive," the FDA's Michele said. "It is an update for most sunscreens available in the United States to better ensure consumers have access to safe and effective sunscreens that are in line with the latest science."

The first update to sunscreen regulations came in the late 1990s, when the FDA added new rules regarding SPF ratings and the use of "broad spectrum" sunscreen, or those that protect from both UVA and UVB radiation. In the early 2000s, the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health put out information that some sunscreen ingredients may be absorbed through the skin.

In 2014, Congress passed the Sunscreen Innovation Act to expedite the review and approval process for over-the-counter sunscreens, giving the agency new tools to review ingredients. While the FDA at that time sought input on ingredients and possible health effects, a formal request for additional data wasn't made until February of 2019, when the agency proposed new regulations.

Michele said the agency typically reviews and evaluates data rather than conducting its own research. In general, the FDA relies on manufacturers to provide data on active sunscreen ingredients needed to establish safety and effectiveness. However, she said the FDA was able to use part of its small research budget to look into absorption of sunscreen ingredients.

"This is one of the first studies done, for any drug, of looking at how much is absorbed into the body," Michele said. "We used to think the skin was like an impermeable barrier, but now we know things can go through the skin and can actually change the drug as it goes through the skin. We have nicotine packets and estrogen packets, and arthritis medication that people rub on. There are all kinds of drugs we give people intentionally through the skin. ... This was the first time someone had looked at absorption in the way that sunscreens are regularly used."

The study, "Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients," was published in May in the Journal of the American Medical Association (JAMA). The study included a randomized clinical trial involving 24 health participants who applied four commercially available sunscreens containing the ingredients avobenzone, oxybenzone, octocrylene and ecamsule. Sunscreen was applied to 75 percent of each participant's body, four times a day for four days, with 30 blood samples collected over a week from each person.

Researchers found plasma concentrations in participants exceeded the FDA's threshold set to require toxicity assessments on drugs to see whether use may result in cancer, birth defects or other health problems.

The Environmental Working Group, which has issued its own guide to sunscreens, has said oxybenzone – one of the most widely used UV-filters – is particularly worrisome. The organization failed to respond to multiple requests by Downtown newsmazine to comment for this article.

"Researcher shows that oxybenzone is an allergen that is absorbed into the skin and can be detected in the bodies of nearly every American," EWG stated on its website. "It is also a potential hormone disruptor still used in 60 percent of non-mineral sunscreens. ... In another study, American adolescent boys with higher concentrations of oxybenzone in their bodies had lower levels of testosterone."

The EWG also cites Danish researchers who found eight of 13 sunscreen ingredients allowed in the United States affected calcium signaling of male sperm cells in laboratory tests, which the researchers suggest could reduce male fertility.

Marya Ghazipura, a doctoral researcher with New York University's Marron Institute, is one of the researchers cited by the EWG. Ghazipura's work has included a systematic review of oxybenzone studies involving humans and animals. The review included pooling together combined results from multiple studies.

"The data is really lacking, not only in the United States, but all over," she said. "But studies are finding high urinary concentrations of UV filters. We've also found humans absorb a lot of UV filters, at a rate of up to two percent."

Ghazipura said the findings are concerning because many of the chemicals, such as oxybenzone and avobenzone, have similar structures to BPA, an industrial chemical used in some plastic containers that have been found to leach into food and pose potential issues to fetuses, infants and children, including brain and prostate gland issues, as well as increased blood pressure.

"It's theorized it can pass through the placenta, but no evidence has been found," she said "But it is entering our system. We see it in our urine. And there are higher amounts in men after they shave, and in women after shaving their legs. By making micro-abrasions then applying these products, it can absorb at a higher rate."

Still Ghazipura said there remains a lack of research to determine if the chemicals are harmful to humans.