Sunscreens: More Harm than Good?

You probably know that the sun’s rays can produce free radicals — unstable, highly reactive atoms that can cause cellular damage in the skin, leading to premature aging and even skin cancer. But you may not know that certain sunscreens contain chemicals, like Padimate-O and Parsol 1789, that may actually increase the damaging effects of the sun.

When the sun’s rays meet certain chemicals on your skin, the light is converted from one kind of energy to another, says Alan M. Dattner, M.D., an integrative physician and dermatologist in Manhattan.

If that energy isn’t properly “calmed down,” says Dattner, it can lead to more damage than the sun would cause on its own. And these chemicals can accumulate in your body over time.

So how can you protect against the damaging effects of direct sun without slathering your skin with potentially harmful chemicals?

The Environmental Working Group (EWG), a nonprofit environmental research organization based in Washington, D.C., recommends using a product containing either zinc oxide or titanium dioxide — minerals with a long history of safe use.

Zinc oxide and titanium dioxide scatter or reflect the sun’s rays rather than absorbing them, so they are very effective at preventing sun damage without creating free radicals in the skin. And since traditional formulations of these minerals aren’t absorbed into the skin (thus the white streaks they tend to leave on the skin), there is less risk of the substance building up in your body.

Another benefit of using zinc oxide or titanium dioxide sunscreens is that they are effective at protecting against both UVA and UVB rays.

UVA rays have longer wavelengths, penetrate more deeply into the skin and can even pass through window glass. UVB rays are stronger in the summer and primarily responsible for sunburn. Both can cause long-term damage.

Ingredients you may want to avoid:

  • Padimate-O and Parsol 1789 (Avobenzone): There is evidence that the sun’s light may cause these chemicals to become reactive and cause free-radical damage when they’re absorbed into the skin.
  • Benzophenone, parabens or octy-methoxycinnamate: These chemicals contain estrogen-like properties that can disrupt the development of reproductive organs, according to research conducted by the University of Zurich’s Institute of Pharmacology and Toxicology. Most of us are already exposed to these chemicals through our environments or diets (for example, in the fish we eat), so absorbing the chemicals through our skin just further overwhelms your body with toxins. And children are particularly at risk when using products that affect development.
  • PABA: This ingredient is rarely used today. It can cause a host of reactions and may even increase the risk of skin cancer in certain individuals.

There is some controversy surrounding sunscreens containing nano-sized particles of titanium dioxide or zinc oxide, which can absorb directly into the skin and can readily enter the bloodstream and other body tissues, and have not been proven safe. Yet the EWG recommends several brands that contain nanoparticles, reasoning that the benefits of using an effective sunscreen that doesn’t contain hazardous chemicals outweighs the possible risks of rubbing nano-sized particles on your skin.

The EWG is, however, urging the FDA to require manufacturers to label products that contain nanoparticles as such, since now it’s not always possible to tell which products contain them just by looking at the label.  

For help choosing a sunscreen, check the EWG’s database of sunscreens rated by efficacy and safety. If you aren’t comfortable with the idea of nanoparticles, you can search only for brands that don’t contain them.

Tips for buying and applying sunscreens

  • Choose a sunscreen with a Sun Protection Factor of at least 15. The SPF number tells you about how long you can expect a sunscreen to protect against UVB rays.
  • For example, if your skin would usually turn red after 5 minutes in the sun, an SPF 15 sunscreen should, in theory, protect your skin 15 times longer, or 75 minutes.
  • However, no sunscreen — even an SPF 45 or 50 — should be expected to remain effective for longer than two hours without being reapplied, according to The Skin Cancer Foundation. Reapply sunscreen at least every two hours, especially after swimming or heavy perspiration.
  • Choose a sunscreen that protects against both UVA and UVB rays.
  • Check the expiration date. Over time, the ingredients in sunscreen can deteriorate, so last year’s bottle may not be effective this year. If your product doesn’t have an expiration date, it’s best to buy a new bottle after about a year, or if the product seems to have changed consistency, has a strange odor or has changed color. The active ingredients in sunscreen have a shelf life of about two years, but you can’t be sure how long the sunscreen sat in a warehouse or on the shelf before you purchased it.
  • Apply sunscreen 30 minutes before exposure to the sun whenever possible.
  • Shake well before using, and be sure to apply enough to cover all exposed skin, including ears, shoulders and back of the neck. An ounce — about a shot glass full — is about what you need to cover your body.
  • Take care to not get sunscreen in or too close to your eyes. Large UVA/UVB-blocking sunglasses can protect the areas you aren’t able to cover with sunscreen.
  • Use a second and third line of defense against sun damage, says Dattner. Cover up as well as you can (e.g., try a lightweight long-sleeve overshirt when outside), and wear a hat — especially between the prime sun hours of 10 a.m. and 2 p.m.
  • Ask your doctor about trying antioxidant supplements, both internally and topically, as another way to counteract free-radical damage, suggests Dattner.

Sunscreen care for babies

If you’ve got a small baby, you might wonder whether it’s safe to put sunscreen on him at all. In the past, the American Academy of Pediatrics recommended not applying sunscreen to children under six months of age. But due to an increased worry about early sun damage in babies, the academy has updated its advice.

The AAP now recommends using only a small amount of sunscreen on babies less than six months old to cover exposed areas such as the backs of the hands or face. Covering up with lightweight long-sleeved shirts, pants, and hats — and staying out of the sun altogether whenever possible — is best for infants.

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