Address
341 State St.
Madison, WI
53703

Phone
608-251-3242 main
608-251-4454 rx
608-251-3304 fax
608-251-3853 rx fax
608-251-5339 tty

Store Hours
Mon-Fri 9-7
Sat 10-6
Sun Closed

Store map

« back to articles

Sunscreen
How to Choose It and How to Use It

By Day Host-Jablonski

We all know we should wear sunscreen, and many polls show that sunscreen use is on the rise. But so are cases of sun-related cancer. Skin cancer makes up about half of all cancer cases, with more than one million new cases occurring each year. According to sunscreen researchers, the biggest concerns are that people aren’t using enough sunscreen to fully protect themselves, and that many sunscreens don’t offer complete protection from the sun’s most dangerous rays.

Along with visible light, Ultraviolet Radiation (UVR) reaches the earth through the atmosphere as part of the sun’s electromagnetic field. UVR is divided into three wavelength categories: UVA, UVB and UVC. All UVR has been shown to specifically damage DNA and induce free radical formation in the skin, which can lead to skin cancer. UVA makes up about 99% of the UVR that reaches Earth and has the longest wavelength. It cannot penetrate the skin very deeply, but it is the radiation that causes tanning and may be involved in skin tumor formation. UVB comprises only 1% of Earth’s UVR, but it penetrates the skin relatively deeply and is a major cause of sunburn and skin cell damage. UVC radiation has the shortest wavelength and is the most toxic -- it is lethal to microorganisms and plants as well as carcinogenic to humans. Fortunately, UVC is completely blocked by the ozone layer.

Though you may not feel the effects until you have gone inside, sun damage begins within one minute of exposure. Within 15 minutes, most people have already received a sunburning dose of UV radiation. Sunburns may not be visible or painful right away, but their damage can continue for up to 24 hours if you don’t take steps to cool and heal your skin. Fortunately, sunscreens can help prevent sunburn and skin damage by blocking or absorbing UV radation -- if you choose them appropriately and use them correctly.

The FDA developed the Sun Protection Factor (SPF) rating to standardize sunscreen potencies and help people prevent sunburn. You can calculate the length of sunburn protection a sunscreen offers by multiplying the SPF number by the number of minutes it takes to get a sunburn. For example, 15 minutes x SPF 10 = 150 minutes (2 1/2 hours) of sun protection. When the SPF rating system was designed, its only purpose was to help prevent sunburn, so it only applies to ingredients that help block UVB radiation. This means that, if your sunscreen does not contain UVA-blocking ingredients, your skin can still be damaged without ever getting sunburned. Some researchers speculate that this is the reason skin cancer numbers are rising each year despite reports of increased sunscreen use.

When it comes to choosing a sunscreen, all active ingredients are listed on the bottle so you can easily see what the sunscreen contains. Choosing a sunscreen with a combination of UVA and UVB-blocking ingredients will provide full protection. There are two types of active sunscreen ingredients: physical sunblocks that reflect UVR away from your skin, and chemical sunscreens that absorb UVR before it can penetrate your skin. Knowing the names of a few safe, reliable ingredients will help you find a sunscreen that works for you.

Physical sunblocks are the most comprehensive sunscreen ingredients, as they deflect the entire UV spectrum and protect from both sunburn and skin damage. The most effective and common physical sunblock ingredients are powdered minerals. Titanium dioxide and zinc oxide are naturally-occurring minerals often used in sunscreens. Both are full-spectrum blockers, providing protection from UVA and UVB radiation. When added to lotion and applied properly, the mineral powder forms a fine coating that may appear milky or whitish at first. This coating is the reflective surface of the sunscreen and should become invisible as it binds to your skin.

Chemical sunscreens are usually designed to prevent against either UVA or UVB but are not full-spectrum blockers. In chemical sunscreens, active ingredients bind to the outermost layer of your skin, which is made up of dead skin cells, and from there absorb UV radiation. There is some controversy about what happens to the UVR at this point. The developers of many chemical sunscreens believe that the chemical ingredients transform UVR into harmless heat energy that warms the skin and nothing more. Recent Australian studies, however, have suggested that the UVR may actually be collected by the chemical suncreen ingredients and deposited into the skin, thereby increasing the risk of cellular damage and skin cancer. The only chemical sunscreen in the U.S. that effectively blocks UVA is avobenzone (also known as Parsol 1789). This synthetic ingredient is widely used throughout the world.

Once you’ve chosen the perfect sunscreen you must be sure to use it properly to receive its full protection. This means applying enough sunscreen, applying it early and reapplying often. Adults should use at least one ounce of sunscreen for every full-body application. Sunscreen should be applied 20-30 minutes before you go into the sun to give the active ingredients a chance to bind with your skin and establish a protective layer. You should reapply sunscreen every two hours to maintain maximum protection. If you’ll be in the sun for a long time, choose a higher SPF and reapply it until you reach the time limit of your SPF level. If you are using an SPF sunscreen and have been outside for 2 1/2 hours, you have received a sunburning dose of UV, and reapplying sunscreen at the end of its time limit will not offer you more protection. Once you receive a sunburning dose of UV radiation, you should treat your skin like you would any other burn. Keep cool and apply gentle anti-inflammatory treatments like aloe vera gel and lavender essential oil.

Sunlight is essential to life on earth and provides many benefits, but there is a limit to the amount of sun your skin can healthfully take. Being conscious of sun exposure helps reduce your risks of developing skin cancer, prematurely aged skin and sunburn. Limiting the time you spend outdoors (especially at midday when the sun is most intense) and wearing tightly woven clothing and wide-brimmed hats will maximize your enjoyment without increasing your risk. Stay safe in the sun this summer, and look forward to many more!

Day Host-Jablonski has worked at Community Pharmacy since 2002. As part of our Outreach Team, she creates CP informational pamphlets, organizes events and has managed our website since its revamp in 2004. She has a BA in Environmental Studies and Environmental Science, is quite excitable around topics of environmenal health and is a self-described "ingredients dork."

Sources:

Australian Photbiology Testing Facility at the University of Sydney: www.aptf.com.au

Paula Begoun's Sun Essentials Article: www.cosmeticscop.com/learn

Photodermatology.com, a peer-reviewed German physician's resource on the effects of sun exposure: www.photodermatology.com/sunprotection

EPA's UV Index Monitor (to check the UVR levels in your area): www.epa.gov/sunwise/uvindex.html

American Cancer Society Skin Cancer FAQ: www.cancer.org