Sunscreen is important for protecting the skin from the sun’s powerful rays. My family and I live at a high altitude, so it is a must for us. But finding a safe and effective sunscreen can be surprisingly difficult and confusing, partly because there is disagreement about whether or not particular ingredients are safe or not. I was already quite familiar with many of the concerns about sunscreen, but, to be honest, the issue is even more complicated than I thought before I started doing some more research for this post. So I will try to provide an overview of some of the major concerns related to various sunscreen ingredients and share with you the type of sunscreen that I use and recommend.
There are two basic types of active ingredients in sunscreens: chemical and physical. Chemical ingredients use synthetic chemical UV filters, while the term “physical ingredients” refers to zinc oxide or titanium dioxide, which scatter and absorb ultraviolet radiation. As we will see, both have their pros and cons.
Oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate are commonly used active ingredients. Chemical sunscreens are generally inexpensive and rub on easily, in contrast to mineral sunscreens, which can make the skin look white.
There are a number of concerns related to these types of sunscreens, including the following:
Skin Irritation and Allergies
Some of the chemicals used in sunscreens are associated with skin irritation and/or allergic reactions. Octinoxate, octisalate, avobenzone, and oxybenzone are known to have moderate to high rates of skin allergies (source).
According to the Environmental Working Group, some laboratory studies of several sunscreen chemicals suggest that they may imitate hormones and disrupt the endocrine system (source). Some of them may also be toxic to the reproductive system. In one study, oxybenzone was shown to interact with hormones when fed to animals in high amounts (source). Not everyone agrees, however, that this is a reason to avoid this chemical. According to at least one dermatologist, Darrell Rigel, MD, FAAD, the amount of oxybenzone that the animals (rats) were given in that study far exceeded levels that would ever be reached with normal sunscreen use (source).
Another concern with chemical active ingredients is that they may cause skin damage as a result of breaking down when sunlight acts on them. This is particularly true of avobenzone. Avobenzone filters UVA rays very well, but it is also quite unstable, so other chemicals, such as octocrylene must also be added in order to stabilize it (source). Chemical-based sunscreens may also generate free radicals, which can damage skin cells and DNA (source).
Spray Sunscreens and Inhalation
When sunscreen is used in spray form, there is a question about whether or not adequate amounts of the sunscreen are even being applied. There is also a risk of inhaling it. After inhalation, the chemicals that are in the sunscreen may then be able to enter the bloodstream and other parts of the body if they are not fully cleared from the lungs.
Physical sunscreens (also known as mineral sunscreens) use zinc oxide or titanium dioxide or both as their active ingredients. As I mentioned above, these ingredients work by scattering and absorbing ultraviolet radiation (source). Zinc oxide is an excellent sunblock and protects the skin from both UVA and UVB rays. Titanium dioxide is effective against UVB rays, but less so against UVA rays. That is why it is often used in combination with zinc oxide. As with chemical ingredients, there have been concerns raised with mineral ingredients:
This is a simply a cosmetic concern. Some mineral sunscreens make the skin look very white and pasty, a side effect that some people do not like.
In an effort to reduce the whitening effect of mineral sunscreens, some manufacturers use nanoparticles in their products. A nanoparticle is defined as “a particle smaller than 100 nanometers (nm), or 100 billionths of a meter” (source).
The concern with nanoparticles is that their incredibly small size may allow them to be absorbed into the skin, the bloodstream, and, eventually, into cells and tissues (source). But it is not clear whether or not this is actually the case. Badger Balm states on their website that “Science overwhelmingly shows that particles of zinc oxide greater than 30 nm, when applied to the skin in a lotion or cream based product, do not get absorbed into the body, do not enter the bloodstream, and are not a threat to human health” (source). (It should be noted that Badger used nanoparticles in their sunscreens until 2011. The company began using non-nanoparticles not because it felt that nanoparticles were unsafe, but because many of its customers asked Badger to stop using them.)
The EWG states that nano-powders “could potentially lodge in the lungs and reach the bloodstream, where they could damage internal organs. To date, no such problems have been reported” (source). The EWG website also contains a page that specifically addresses nanoparticles. They state on this page that “some studies indicate that nanoparticles can harm living cells and organs, but there is no evidence that zinc oxide and titanium dioxide nanoparticles penetrate skin in any significant quantities” (source). They also cite a 2010 study in which human volunteers applied zinc oxide sunscreen with particles of either 19 or 110 nm two times a day for five days. In both groups, researchers found less than .01 percent of the zinc in the bloodstream (source). Studies of titanium dioxide by the FDA and the European Union had similar results (source). It appears, then, that nanoparticles generally do not penetrate the skin. As with everything, though, there are exceptions. If the skin is broken, as is the case with eczema and other skin irritations, then nanoparticles might be allowed to the enter the body (source).
If you have eczema or broken skin, or if you just want to err on the side of caution, choose a sunscreen that is specifically labeled as non-nano. As I mentioned before, Badger’s sunscreens use non-nanoparticles. Be aware, however, that because of the difficulty in measuring all particles in a product, it is nearly impossible for manufacturers to guarantee that 100 percent of their zinc oxide or titanium dioxide is non-nano (source).
Another concern with mineral sunscreens is the risk of inhaling small particles of zinc oxide or titanium dioxide. Inhalation is not a risk with sunscreen lotions, but it is a problem when it comes to mineral sunscreens in spray form (source). For this reason, the EWG strongly discourages the use of such sunscreens: “Inhalation is a much more direct route of exposure [from zinc oxide and titanium dioxide] than skin penetration, which appears to be low in healthy skin” (source). The issue is that the lungs have difficulty clearing small particles, so they can pass into the bloodstream. Zinc oxide can also be inhaled when making homemade sunscreens, so it is extremely important to cover your mouth and nose with a mask when making sunscreen at home.
As you can see, choosing a safe sunscreen can be overwhelming; there are so many variables to consider! I personally opt for using mineral sunscreens when I am going to be in the sun for more than about 30 minutes. I avoid chemical sunscreens because of the concerns listed above, the one about hormone disruption in particular. While oxybenzone may only affect hormone function when used in high amounts, I would rather not take a chance. And I avoid chemical sunscreens for another reason: we don’t really know how the chemicals in sunscreen interact with each other or with the chemicals found in other personal care products.
I have noted that mineral sunscreens are not without their drawbacks, either. However, after having studied and revisited the issue for several years, I believe that, in lotion form, they are the safest option. Based on the information that we currently have, I believe that zinc oxide and titanium dioxide particles (even if they are nano) are very minimally absorbed by the skin and that they are safe and effective sunscreens. It is my opinion that the biggest risk from mineral sunscreens is inhalation, which is why spray forms should be avoided and precautions must be taken when making homemade sunscreens. I use Badger sunscreens because they produce very effective mineral sunscreens that generally contain only 100 percent natural inactive ingredients. I also make my own sunscreen.
Sunscreen is of course only one option for protecting the skin. Avoiding direct sunlight during the middle of the day (from 10 a.m. to 2 p.m.) and wearing protective clothing, such as hats, long pants, and long sleeves, are also important. Eating high antioxidant foods can also help protect the skin from damage caused by the sun’s radiation.
Challem, Jack. “A Day in the Sun: Protection Inside and Out.” Natural Grocers, 23 July 2013. Web. 31 March 2014.
Collins, Sonya. “Sunscreen Safety: What to Know.” WebMD, 27 November 2012. Web. 30 March 2014.
“Nanoparticles in Sunscreens.” The Environmental Working Group,” Web. 29 March 2014.
“Sunscreens: How it Works, What it Means.” The Environmental Working Group, Web. 6 April 2014.
“The Trouble with Sunscreen Chemicals.” The Environmental Working Group, Web. 29 March 2014.http://www.ewg.org/2013sunscreen/the-trouble-with-sunscreen-chemicals/
“Zinc Oxide Sunscreen and Nanoparticles.” Badger Balm, Web. 30 March 2014.
Disclosure: I have not received any compensation from Badger Balm for my endorsement of their sunscreens. Badger sunscreens are simply my preferred brand of commercial sunscreens.