There’s been a lot of discussion lately as to terminology for sun protection products. I saw a news broadcast the other day where the news anchors all discussed what terms were currently in use today. The question posed was what term do you use to refer to your sun protection product. The three options given were Tan Lotion, Sun Screen and Sun Block. This type of discussion trivializes the importance of understanding the risks of sun exposure as well as the risks of the products used to mitigate sun exposure. What they did not seem to realize was that these three terms do not refer to the same thing and are not simply a colloquialism indicating the times.
Suntan lotion is a generic term that was used when the sun protection products such as Coppertone were marketed. It refers to a lotion with a small SPF measure usually no more than 8, often times closer to 2, that is used to block UVB rays, but not UVA. The intent is to moisturize the skin and allow a longer amount of time in the sun before burning.
Sunscreen is a chemical product that penetrates into the skin and absorbs UVA rays. UVA rays are responsible for oxidation and skin damage, but do not cause a sunburn.
Sunblock is a physical barrier that shields against UV rays including UVA and UVB. The FDA no longer allows the term to be used commercially as it can be misconstrued to cause the user to believe they are getting more protection than they actually are.
A small explanation about UV. There are three kinds of UV (ultraviolet) light that comes from the sun. UVA has longer wavelengths and penetrates further into the dermis which is why it can cause DNA damage. UVB has shorter wavelengths and is responsible for sunburns. UVC has an even shorter wavelength, but is absorbed by our ozone layer so is not a cause for concern.
The types of chemical sunscreens are octyl methoxycinnamate also known as octinoxide, octyl salicylate aka octisalate and octocrylene. According to the Environmental Working Group all of these have potential issues with endocrine disruption, bioaccumulation, and are allergenic. While it has been known for some time that these ingredients may have potential impacts as endocrine disruptors or allergens, it was not known that they are persisting in the skin longer than just during general use.
Since we are all becoming more aware of the risks of skin cancer due to sun exposure on a daily basis people are using these these products on a daily basis instead of just during longer durations of exposure. The persistence of these chemicals in our systems is more like a few weeks and the impact of these chemicals was likely not assessed for this type of exposure. Because of this we should all be cautious.
The most widely known physical sunblocks are zinc oxide and titanium dioxide. These are widely used and can generally be recognized by the whitish cast left on the skin. This is because they sit on top of the skin rather than penetrating. While these are more effective in preventing skin damage from UVB rays they are less popular due to the heavier nature of the product. Manufacturers are getting better at formulating this in a lighter consistency.
According to a 1997 study conducted by the Federation of European Biochemical Societies titanium dioxide (TiO2) absorbs about 70% of incident UV, and in aqueous environments this leads to the generation of hydroxyl radicals which can initiate oxidations. These oxidations are known as free radicals. “Free radicals seek to bond with other molecules, but in the process, they can damage cells or the DNA contained within those cells. This in turn could increase the risk of skin cancer.”
These studies have shown that in shorter duration these physical sunblocks are effective but in longer duration there is potential for them to oxidize and release free radicals. Free radicals are the bane of our skin’s existence by causing damage to the skin’s ability to function normally which in turn cause premature aging and inflammation and potentially cancer.
So what is a person supposed to do? Ultimately we should all avoid spending longer amounts of time in direct sun. Shade is an effective way to avoid getting burned, but it is not able to prevent all sun damage. This is because the sun’s rays get reflected off of surfaces which means you are still getting UV indirect exposure and potentially oxidation.
Can we feel confident just finding a tree to hide under? Not really. “Factors that increase the amount of scattered or indirect UVB, such as reflective surfaces, will decrease the protection trees can provide. The same tree actually gives less protection earlier and later in the day, when the proportion of diffuse UV is high, than it does in the middle of the day when the sun is more directly overhead. Similarly, someone sitting under a tree on a sunny day with little indirect UV is better protected than someone sitting under the same tree on a cloudy day, when there is more indirect sunlight.15 However, any tree cover is better than none.” (Skincancer.org)
Since we all live in the real world and can’t always plan the time of day or the type of tree, we seek shade from, we should seek to mitigate the risk of exposure by pairing the sunblock products with antioxidants.
Antioxidants counteract free radicals because they’re essentially “self-sacrificing soldiers.” … they donate an electron to free radicals to “calm” them down and are consumed in the process. (Dr. Axe)
There are many antioxidants, but some of the most widely used and stable are carrot seed oil, vitamin E, vitamin C, grape seed which includes both vitamins E and C. Vitamin C is also an effective collagen booster which is why you will find it used in many facial serums.
Many sunblock products formulated today have already taken these steps and included carrot seed oil, myrrh, lemongrass, lavender, chamomile…
Please feel free to check out some of my hand-picked sun protection products.
Source: An in vitro systematic spectroscopic examination of the photostabilities of a random set of commercial sunscreen lotions and their chemical UVB/UVA active agents – Photochemical & Photobiological Sciences (RSC Publishing)
Source: Characterization of DNA Damage Inflicted by Free Radicals from a Mutagenic Sunscreen Ingredient and Its Location Using an in vitro Genetic Reversion Assay – McHugh – 1997 – Photochemistry and Photobiology – Wiley Online Library
Source: Photochemical Formation of Singlet Molecular Oxygen in Illuminated Aqueous Solutions of Several Commercially Available Sunscreen Active Ingredients – Chemical Research in Toxicology (ACS Publications)
Source: Development of assays for the detection of photomutagenicity of chemicals during exposure to UV light. II. Results of testing three sunscreen ingredients | Mutagenesis | Oxford AcademicSource: Sunscreen May Not Have It Made in the Shade | Flashback | OZY