Can You Get Cancer From Sunscreen?
Separating Fact From Fiction
The benefits of daily sunscreen use are absolutely clear. Research has shown when you wear a broad-spectrum sunscreen rated SPF 15+ properly (applying liberally, reapplying after more than a few hours in direct daylight) every day, your risk of deadly or disfiguring skin cancer dramatically decreases (not to mention premature aging, i.e. wrinkles, brown spots, and skin sagging).
An Australian study done in 2013 showed that when a well-formulated sunscreen is applied to exposed skin as directed, it offers 100% protection against all three types of skin cancer. What's more, regular sunscreen use also protects an anti-cancer gene in skin known as p53 from becoming damaged. Sunscreen does a lot more than just protect against sunburn and premature aging (Source: Pigment Cell and Melanoma Research, November 2013, pages 835-844).
Not surprisingly, research published in the Journal of the American Medical Association, a randomized, 10-year study of 1600 adults reinforces that using an SPF 16 reduces your risk of skin cancer. Given that fact, imagine the benefits of using an SPF 20 or 30? Despite these long-established benefits of using a daily sunscreen, there is still ongoing controversy regarding their safety. If you've fed into this fear and stopped using sunscreen, we implore you to read on for the facts.
If these unsubstantiated claims of sunscreen causing cancer (meaning carcinogenic) fears were actually true, one would expect cancer rates to increase (especially among those that work in the cosmetic industry, as they are surrounded by high concentrations of these "suspect" ingredients). Yet, the medical data does not support this, as overall incidences of cancer have declined in the US, per 2012 statistics from The American Cancer Society.
The following sunscreen ingredients are among the most maligned and disparaged for their safety profile, so let's look beyond the distortions to what the research really says.
Vitamin A: The Unjustly Accused Antioxidant
Retinyl palmitate is a natural form of vitamin A that is stored in your skin, providing multiple benefits from neutralizing free radicals and reducing the risk of sunburn. Retinyl palmitate is approved for use globally in sunscreens. Yet this essential vitamin has been said to increase skin-cancer risk because of a single, unpublished ten-year old study (re: the study has not been peer-reviewed, or tried under different conditions).
Researchers in that study didn't test sunscreens containing retinyl palmitate (of which use very small amounts of the antioxidant), rather they applied high concentrations (i.e. much greater than what is used in cosmetics products) of retinyl palmitate directly to rodent skin! This isn't at all representative of how retinyl palmitate is used in skin care formulas—and researchers used a rodent breed that is predisposed to skin cancer (80% the mice who were exposed to UV light alone, without retinyl palmitate, developed skin cancer anyway).
- The Skin-Cancer Foundation's Photobiology Committee, in their recent assessment of the sunscreen controversy, states "There is no scientific evidence that retinyl palmitate causes cancer in humans..." and, "no published data suggests that topical retinoids increase skin cancer risk."
- Memorial Sloan-Kettering Cancer Center, in their 2011 peer-reviewed, published study in Photodermatology, Photoimmunology & Photomedicine, reviewed the data cited noting, "In conclusion, the available evidence from in vitro and animal studies fails to demonstrate convincing evidence indicating that retinyl palmitate imparts an increased risk of skin cancer."
Conclusion: As noted by the Memorial Sloan-Kettering Cancer Center, "decades of clinical observations support the notion that retinyl palmitate is safe for use in topical applications such as sunscreens."
Oxybenzone: Is It Really Dangerous?
Oxybenzone is a sunscreen active that's been in use for over 20 years, the safety data on it is exhaustive and as it is globally recognized as a safe and effective sunscreen agent. Headlines hoping to get your attention love regurgitating that minute levels of oxybenzone are absorbed by skin, of which trace amounts (one millionth-per-gram, that is infinitesimally small,) can be detected in urine (per a 2008 CDC report).
While that may sound alarming, the presence of substances like oxybenzone in urine doesn't denote anything on its own. Research using volunteers have looked at the effect, rate of absorption, and potential of oxybenzone to accumulate (otherwise, it is just your body metabolizing substances as it should). A 2004 study in Journal of Investigative Dermatology and a 2008 study in the Journal of the European Academy of Dermatology & Venereology demonstrated by applying a full-body application of a 10% concentration of oxybenzone over the course of 4 days had no negative health effects, and did not accumulate in the body. Other points to confirm the safety of oxybenzone include:
- The American Academy of Dermatology states, "No data show[s] that oxybenzone causes any significant health problems in humans."
- The Skin Cancer Foundation Photobiology Committee agrees, noting, "There is no evidence that oxybenzone, which is FDA-approved and has been available 20 years, has any adverse health effect in humans."
- The Memorial Sloan-Kettering Cancer Center 2011 study in Photodermatology, Photoimmunology & Photomedicine, concludes "the available evidence does not demonstrate biologically significant hormonal disruption with topical application of oxybenzone in humans."
- The scientific and regulatory bodies of the European Union produced a 2008 report, Opinion on Benzophenone-3, that they found oxybenzone in sunscreens "does not pose a risk to the health of the consumer."
Conclusion: Numerous investigative studies spanning the globe continue to confirm oxybenzone's place as a long-established safe UV protectant.
Octinoxate: A Misunderstood SPF Hero
Also known as octyl methoxycinnamate or ethylhexyl methoxycinnamate, octinoxate is the oldest and most common sunscreen active with a solid record of safety (decades of research and thousands of studies establishing its safety in sunscreens as indisputable). Unfortunately, unfounded claims that this staple of SPF formulas "causes cancer" have made many afraid of their sunscreens. Let's be clear: no studies demonstrate octinoxate when used in your SPF products causes, or increases the risk for developing cancer. In the sole studies cited when the "octinoxate = cancer" claim is made, the conditions are completely inapplicable to how sunscreens ingredients are used in skin-care products.
For example, such studies use octinoxate in high concentrations (much higher than would ever be used in sunscreens) applied directly to skin cells, or fed in high concentrations to lab animals. The moral here is that octinoxate is safe as long as you aren't drinking it!
Conclusion: No studies exist that back the claim octinoxate has any link to causing cancer or other illnesses when used in sunscreen formulas. In fact, the EU's usage level for octinoxate in sunscreens is higher than what is permitted in the United States (7.5% in the US vs. 10% in the EU).
Nanotechnology: Does Size Really Matter?
Nanotechnology is used in different arenas like medicine and manufacturing, and refers to a range of particle sizes that are anywhere between 1 to 100 nanometers. The difference between 1 and 100 nanometers would be similar to comparing the size of you to, well, you multiplied by 100!
In the vast range of applications and substances where nanotechnology is used, it is as meaningless to categorically state "all nanoparticles are dangerous" as it is to say "all red things are hot." The size and substance make all the difference! So, when asking the question of whether nanoparticle sunscreen ingredients [titanium dioxide & zinc oxide] can penetrate skin and enter the bloodstream, it's important to ensure we're looking at the right information.
Here are the facts:
- Titanium dioxide and zinc oxide are sized (at the high end of scale, towards 100 nanometers) and polymer-coated to ensure they remain on the surface of skin—otherwise they wouldn't be very good at working as sunscreen actives!
- FDA scientists, in a 2007 study published in The Toxicologist Journal [The Society of Toxicologists], demonstrated in human skin that nano-sized particles, "were found predominately in the stratum corneum and they did not penetrate through the skin."
- Australian and Swiss research teams, using excised human skin in two separate 2011 studies published in the Biomedical Optics Journal, established that neither nano-sized titanium dioxide nor nano-sized zinc oxide penetrated beyond the superficial layer of skin (stratum corneum).
- The Environmental Protection Agency released a 2010 case study of nano-scale titanium dioxide in sunscreen formulas, stating there is no health problem/concern associated with its use. Their findings also confirmed nano-sized titanium dioxide did not penetrate beyond the superficial layer of human skin.
- The Memorial Sloan-Kettering Cancer Center published a review of nanoparticle titanium dioxide and zinc oxide in Photodermatology, Photoimmunology & Photomedicine, stating, "It has been established that the stratum corneum is an effective barrier preventing the entry of nano-ZnO [zinc oxide] and -TiO2 [titanium dioxide] into deeper layers of the skin."
What of recent media mentions of zinc oxide and free-radical damage increasing cancer risk? This erroneous news story deserves an article all to its own, Zinc Oxide: Does it Really Increase Your Risk of Cancer?
Conclusion: There is no evidence that nano-sized titanium dioxide or zinc oxide sunscreen actives pose any health risk (and certainly not in comparison to skipping, or skimping, on your SPF).
It is worth mentioning that the discussion above should also provide evidence that research into the safety and applications of cosmetic and skin-care ingredients never stops. Globally, extensive and continuous scientific and medical research has shown your sunscreen remains safe to use, and unprotected exposure to the sun itself is the"toxin" of which you should be concerned. Along with other practices such as limiting sun exposure, wearing sun-protective clothing, hats, and sunglasses, reapplying sunscreen as often as needed is critical to reduce your risk of skin cancer and numerous signs of aging.
Sources: Biomedical Optics Express, 2011, pages 3278-3283; Biomedical Optics Express, 2011; page 3321; British Journal of Dermatology, 2009, pages 630–634; Cancer Journal for Clinicians, 2012, pages 10–29; Environmental Health Perspectives, page 116; Journal of the American Medical Association, 2011, pages 302-303; Journal of Dermatological Science, 2009, pages 10-18; Journal Of Investigative Dermatology 2003, pages 1163–1167; Journal Of Investigative Dermatology 2004, pages 57–61; Mayo Clinic Proceedings, 2012, page 328; Photodermatology, Photoimmunology & Photomedicine, pages 58–67; The Toxicologist, 2007, page 289; U.S. Environmental Protection Agency, 2009.
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