What You Must Know About the Chemicals in Your Sunscreen
You probably don’t need to be told (again) how important wearing sunscreen is for reducing your risk of skin cancer, not to mention sunburns and signs of premature aging (think wrinkles). But go ahead and Google "best sunscreens" or even "sunscreen," and plenty of articles pop up suggesting that the ingredients in many of these products could be harmful or even toxic, leaving you to worry about what's really going on your skin. And maybe even wonder whether it's actually safer to go outside without a protective spray or lotion?
The answer: No. In fact, the skin experts Health talked to were adamant that we should be more worried about shielding our skin from the sun's harmful UV rays than about the chemical makeup of the products we're using to do that.
“Five million Americans are treated for skin cancer each year, and an estimated 9,940 people will die of melanoma"—the deadliest type of skin cancer—"in 2015," Steven Wang, MD, head of dermatological surgery at Memorial Sloan Kettering Basking Ridge in Basking Ridge, New Jersey, told Health. “The biggest precaution that you should be taking is using sunscreen. There is enough research at this point from various credible bodies that say sunscreens are safe and, when used appropriately, will reduce skin cancer.”
Why you might have heard that sunscreen could be dangerous
So, where are people getting the idea that the chemicals in certain sunscreens are potentially hazardous?
For starters, there has been much concern about chemicals thought to be endocrine discruptors in our everyday environment in recent years. Proven endocrine disruptors, which include bisphenol-A and pesticides like DDT, can mimic the hormone estrogen in the body, which may increase risk in humans for low fertility, endometriosis, and certain cancers.
Most recently in regards to sunscreen, a report this year from the Environmental Working Group (a non-profit advocacy organization) once again made reference to "worrisome ingredients like oxybenzone and Vitamin A" commonly found in these protective products.
But the thing is, the actual research on the effects of these "worrisome" ingredients in sunscreen may have been blown out of proportion.
Take this 2008 study in the journal Environmental Health Perspectives, for example, which examined concentrations of benzophenonone-3 (a.k.a. BP-3, or oxybenzone) in residents of the United States. The researchers concluded that while exposure to the chemical was prevalent in the population studied, "human exposure to BP-3 has not been associated with adverse health effects."
Some studies do suggest that the chemical could potentially have effects on the endocrine system, but, the scientists explain, that research was conducted on animals—including some in which mice and rats were fed oxybenzone orally—and animal tissue isolated in labs.
In 2011, Dr. Wang and colleagues published a research letter in JAMA Dermatology titled: "Safety of Oxybenzone: Putting Number into Perspective." For that paper, the researchers, took the dose used in one of the most worrisome studies on oxybenzone in rats and determined that an equivalent dose in humans would amount to almost 35 years of daily, full-body application.
And even though there is evidence that oxybenzone does get absorbed by your skin and excreted via urine, the authors of another 2004 paper concluded that despite the presence of the chemical in participants' urine, they observed no hormonal changes that could be traced back to the sunscreen exposure.
As for vitamin A, commonly found in products like sunscreen in the form of retinyl palmitate, the backlash stems from findings from the National Toxicology Program (NTP), which is a U.S. government program that tests and evaluates chemicals in our environments. One of the NTP's oft-cited experiments found that retinyl palmitate cream applied to hairless mice exposed to UV radiation in a lab increased the incidence of skin tumors as well as the speed at which the tumors developed, compared to control groups of mice that weren't covered in the cream.
But again, this isn't comparable to the effects of this additive in human skin because, for one thing, the researchers looked at retinyl palmitate "in isolation," according to a 2010 critical analysis in the Journal of the American Academy of Dermatology. Retinyl palmitate is an antioxidant naturally found in human skin, along with vitamins C and E. And these three actually work together in a way that neutralizes any negative effects, the researchers report.
On top of that, as the researchers write in response: "It is important to mention that the mice in the above NTP study are highly susceptible to develop skin cancer after UV exposure... mouse epidermis is significantly thinner than that of human beings, hence resulting in higher percutaneous absorption. Therefore, extreme caution is needed when extrapolating these animal study results to human beings."
The bottom line from the Skin Cancer Foundation: "[C]onsumers should rest assured that sunscreen products including the ingredients oxybenzone and retinyl palmitate are safe and effective when used as directed. Both oxybenzone and retinyl palmitate"—which is a form of vitamin A—"are approved for use in sunscreens by the U.S. Food and Drug Administration (FDA). The Skin Cancer Foundation’s position is based on years of clinical data."
How to choose the right sunscreen for you
First, a little skepticism can be helpful. “A lot of these articles [about sunscreen] are A+B = Z. There’s so many steps in between the science that they don’t discuss,” Ellen Marmur, MD, a New York City-based dermatologist, explained to Health. “You have to look at your sources, you have to trust that they are referencing their articles correctly. If it seems really radical, it’s probably not the whole truth.”
The very best sunscreen to use is simply the one you like and will actually reapply, often. So if that means you'd rather not use chemical sunscreens for whatever reason, that's your call. There are plenty of sunscreens that rely on zinc oxide and other physical blocks that work just as well to protect your skin.
Dr. Wang, who's also a spokesperson for the Skin Cancer Foundation, encourages the use of a water-resistant broad-spectrum sunscreen with an SPF of 30 or higher and reapplying every two hours or after swimming or sweating excessively. Be sure to apply two ounces of sunscreen—to help you visualize, that's the amount that would completely fill two shot glasses—to your entire body 30 minutes before heading outside, coating every part of your skin. When you reapply, use one ounce (so, one shot glass full) each time.
And don't forget: sunscreen is just one part of a complete sun-protection regimen, our experts add. Don't be shy about seeking shade between the hours of 10 am and 4 pm, wearing a wide-brimmed hat, and UV-blocking sunglasses in addition to using sunscreen, all in the service of lessening your exposure to UV radiation. Says Dr. Wang: "That is the real threat, not whether or not sunscreen is safe.”
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