Sunscreen Basics - Appalachian Spring Dermatology

The most common question I am asked is , “Which SPF should I get?” 

As you will read, you will learn that I care more about the active ingredients than the SPF, here’s why:

SPF measures the length of time a product protects against skin reddening from UVB, compared to how long the skin takes to redden without protection. If it takes 20 minutes without protection to begin reddening, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer – about 5 hours. (Actually, it may take up to 24 hours after sun exposure for redness to become visible.) To maintain the SPF, reapply sunscreen every two hours and right after swimming.

The Skin Cancer Foundation recommends SPFs of at least 15, which blocks 93 percent of UVB. While SPFs higher than 30 block only 4 percent more UVB, they are advisable for sun-sensitive individuals, skin cancer patients, and people at high risk of developing skin cancer. They also allow some margin for error if too little sunscreen is applied. Considering that the SPF is developed using a whole ounce to the entire body, most everyone does not apply enough sunscreen and does not get the full SPF suggested on the label.

While SPF is the universal measurement of UVB protection, no comparable standard exists for UVA. Scientists worldwide are working to develop a standardized testing and certification method to measure UVA protection.   Also, there is no effective measurement for protection against blue light HEV and Infrared that is now also known to be harmful.

Even with the ideal sunscreen, some UV rays can get through to your skin and cause damage. The Skin Cancer Foundation considers sunscreen one part of a comprehensive sun protection program, along with sun-protective clothing, sunglasses, shade, and sun avoidance from 10 A.M. to 4 P.M.

What kind of light is the most harmful? 

UVB (Ultraviolet-B)  Short-wave solar rays of 290-320 nanometers. More potent than UVA in producing sunburn, these rays are considered the main cause of basal and squamous cell carcinomas as well as a significant cause of melanoma.

UVA (Ultraviolet -A) Long-wave solar rays of 320-400 nanometers. Although less likely than UVB to cause sunburn, UVA penetrates the skin more deeply, and is considered the chief culprit behind wrinkling, leathering, and other aspects of “photoaging.” The latest studies show that UVA not only exacerbates UVB’s carcinogenic effects but may directly induce some skin cancers, including melanomas.

I recommend an SPF>30.  Make sure the bottle says that it protects against UVA and UVB, preferably 100% of UVA and UVB.  Remember that sunscreens generally wear off, or the chemical breaks down in 2 hours.  So sunscreen needs to be reapplied throughout the day.     I particularly like sunscreens containing zinc oxide and titanium dioxide.  Zinc and titanium are physical barriers that work much better and last longer than the chemical sunscreens. Zinc has a more complete and broader coverage than titanium.

The new issues to discuss includes not just UV protection but also protection from HEV and Infrared rays.  Increasing data suggests that these sources of light cause additional damage to the skin.

HEV (High-energy visible (HEV) radiation) This radiation, also known as “blue light,” actually includes light from 400-500nm, and it can be just as harmful to skin, leading to inflammation, impaired healing, wrinkling, and discoloration. The most common sources of HEV include computers, television, phone, and iPad screens.  Studies have shown that melanin (the pigment our body naturally makes) is the best protector against HEV in the skin.  Many sunscreens are starting to incorporate melanin in them to block against HEV.

IR (Infrared radiation)  Infrared radiation is what provides that warm sensation in the sun.  According to the atlas of science, “ The spectrum of solar radiation reaching the Earth is divided as follows: 6.8% UV, 38.9% visible, and 54.3% near-infrared radiation (NIR). IR has been divided into three bands: IR-A (760–1400 nm), IR-B (1400–3000 nm), and IR-C (3000 nm – 1 mm). IR radiation can penetrate in and under the skin, depending on the exact wavelength range being studied. Exposure to IR is perceived as heat.”   There is still some scientific disagreement about the extent of the impact of infrared exposure on the skin.  At this time, we can say that protection against IR is a plus. More recent evidence suggests that infrared rays increase the activity of matrix metalloproteinases, which degrade collagen and increase the aging of the skin.

Photolyases. Photolyases work to correct DNA damage caused by sun exposure. Photolyases, DNA repair enzymes occur naturally in the skin but are now available to apply topically. Products containing photolyases not only protect but ACTIVELY REPAIR the skin as well. Most products containing photolyases utilize an extract of Artemia Salina. Antiaging products containing DNA repair enzymes have been available commercially for a few years in products such as ZO Daily Power Defense, but combining them with sunscreen at an affordable price point is new and exciting. We carry the first sunscreen containing photolyases in the Spring Boutique. It is made by ISDIN and is called Eryfotona Actinica. One study showed that in addition to protecting the skin, using a topical sunscreen containing photolyase could also decrease the number of active actinic keratoses. There are a few newer of these for 2020, one by Skin Ceuticals and one by Neova. VERY EXCITING!

SO, HOW DO I CHOOSE?

1 -Check the Active Ingredients – I particularly like sunscreens containing zinc oxide and titanium dioxide.  Zinc and titanium are physical barriers that work much better and last longer than the chemical sunscreens. Zinc has a more complete and broader coverage than Titanium. Sunscreens that incorporate melanin also block against HEV. Artemia salina gives those DNA repair enzymes. 

2-Check the Water Resistance– At least 80 minutes water resistance is optimal.

3-Decide if you will actually use it! Pick one that you like the smell, feel and look of, AND one you can easily toss into a bag, so it’s there when you need it. I work hard to find sunscreens that meet individual needs. We carry things that are not easily commercially available in our Spring Boutique, where you can try them out.

The best sunscreen is the one you actively use! This is the first in a series of sunscreen posts for 2020, stay tuned for “What is trendy in sunscreen for 2020” and “Dermatologist Sunscreen Picks for 2020”. To make sure you receive all of these articles, sign up for our blog posts at our website www.wvderm.com.