Shedding Light on Sun Safety - Part Two

by Dr. Claudia Aguirre

Currently, there are a variety of options for sunscreens. You may want to use physical blockers of UV rays, an array of chemical ingredients that absorb UVA and UVB rays, or a combination of both types. There are some differences to these, and recently the chemical ingredient Oxybenzone has been in the news as a no-go for sunscreens. Before we delve into the topic of Oxybenzone, let’s review the main differences between chemical and physical sunscreens.

Chemical vs. Physical

To make matters more confusing, there are several ways to describe the different types of sunscreens available today. In the scientific community, these sunscreens are referred to as organic or inorganic filters. No, this does not refer to whether or not you’ll find them at your local natural grocery store. Instead, it refers to whether or not it contains a carbon atom. So if any chemical compound includes carbon atoms, it is referred to as ‘organic.’ Organic filters include the chemical sunscreens found in many formulations. Inorganic filters are more commonly referred to as physical or mineral sunscreens. These include the physical compounds zinc oxide and titanium dioxide. These physical sunscreens sit on the skin and scatter or reflect UV rays. On the other hand, chemical sunscreens typically absorb the UV rays. These include ingredients such as Avobenzone, Oxybenzone and Homosalate, among others.

OK But Which Is Better?

There are lots of options for sunscreens, and most formulations will use a combination of physical and chemical sunscreens. All of the previously mentioned chemical and physical ingredients have been approved by the FDA. There isn’t a better option because they are all so different. However, there are cases where some chemical compounds may cause skin reactions such as dermatitis, whereas the physical blockers typically do not. Keep in mind that the reaction is often due to the high level of fragrance or alcohol used in sunscreen products. For a sensitive skin, it may be more suitable to use a physical sunscreen. So is physical better than chemical? Not exactly. It depends on the formulation and the preference of the client. Chemical sunscreens were developed to provide versatility in formulations, allowing for invisible coverage while providing UV protection. Physical sunscreens are excellent for sensitive skin, provide superior coverage but can leave a white cast to the skin.

What’s The Issue with Oxybenzone?

Good question. The recent report published online by the Environmental Working Group (EWG) has blacklisted Oxybenzone as a hormone disruptor that penetrates deeply into the skin. What exactly is a hormone disruptor? Also known as an endocrine disruptor, it refers to an external compound that disrupts the physiological actions of our body’s natural hormones. It was coined in the 90s and has typically referred to environmental chemicals, such as pollutants. However this term encompasses an extensive list of chemicals all living beings breathe, eat, walk over, swim in, or simply are exposed to. The EWG report states that Oxybenzone is a potential hormone disruptor, although they once again extrapolate data from scientific studies to assess daily human use and risk. One study they cited (Schlumpf et al 2001) did show estrogenic effects on rats after ingestion of Oxybenzone. However, it is important to note that these animals were exposed to large amounts (more than the recommended for human use) of Oxybenzone via routes not used by humans, namely the mouth. So these results only apply to rodents eating large amounts of Oxybenzone, not humans spreading an Oxybenzone-containing cream over their skin. Another study on humans with more natural conditions could not confirm this data (Janjua et al 2004). In 2001, the Scientific Committee on Consumer Products and Non-food Products (SCCNFP) concluded that sunscreens do not have an estrogenic effect that influences human health. Let’s imagine that there is a risk of Oxybenzone to be a hormone disruptor. To do this it would have to penetrate deep into the living dermis. The EWG claims that this is the case, citing a study on Oxybenzone and penetration (Hayden 1997). However, they do not mention that this study was done in vitro, meaning they looked at the absorption in skin samples in the lab, and not on a human being. Another study by the same group saw deleterious effects on humans; however the fine print is that the participants were asked to use about 6 times the recommended amount of sunscreen needed to prevent sunburn. Again, these studies do not prove that Oxybenzone penetrates at the recommended levels. There is scientific research that supports the safety of this compound for human use. These confirm that sunscreen products formulated with 1-6% Oxybenzone do not possess significant sensitization potential and toxicity to the underlying human keratinocytes after topical application to the skin. The Scientific Committee on Consumer Products (SCCP) of the European Commission concluded in 2008 that it does not pose a significant risk to consumers, apart from contact allergenic potential.

So What Should I Do?

The studies and scientific committees have provided evidence that it is safe to use for consumers. However, it must be noted that babies do not rid themselves from toxins as readily as adults, and their skin may be more penetrable. That is why the FDA requires a warning on all sunscreens “not to be used on children under 6 months of age.” If you happen to be one of those individuals that experience breakouts or irritation with chemical sunscreens, then we recommend that you choose a physical blocker to protect the health of the skin.

Sunscreen Isn’t Fail-Safe

Sunscreens are only one option to protect you against harmful UV rays. Using more certainly does not warrant more time out in the sun; nor should you avoid it due to misinformation. In fact, there is no evidence that sunscreens protect you from malignant melanoma, the deadliest form of skin cancer. However, sunburns have been linked with the development of melanoma – and sunscreens have been shown to prevent sunburns. So be sun smart! Don’t be a vampire but protect yourself from UV rays by seeking shade, wearing UV protective clothing, and choosing from the variety of approved sunscreens.

References:

1. Agin P et al. Photodermatol, Photoimmunol & Photomedicine (2008) 24:211-217
2. Gonzalez H. Percutaneous absorption with emphasis on sunscreens. Photochemical & Photobiological Sciences (2010) 9: 482–488
3. Hayden C et al. Lancet (1997) 350:863-864
4. Hayden, CGJ et al. Skin Pharmacol Physiol (2005) 18:170–174
5. Janjua NR et al. J Invest Dermatol (2004) 123:57-61
6. http://www.health.gov.au/internet/skincancer/publishing.nsf/Content/fact-2
7. http://progressreport.cancer.gov/doc_detail.asp?pid=1&did=2007&chid=71&coid=711&mid=#target
8. http://www.skincancer.org/Skin-Cancer-Facts/

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Shedding Light on Sun Safety - Part Two