Debunking 5 Common Sunscreen Myths

March 31, 2021

woman applying sunscreen

When it comes to caring for skin, dermatologists know that every person has unique needs, and helping people find the perfect products and skincare routine is an essential part of what dermatologists do. If there’s one exception, it’s that everyone needs to wear sunscreen. According to Dr. Robert Marinaro of U.S. Dermatology Partners in Richardson and Sherman, Texas, “No matter what your skin type or tone or your skin health history, you need to wear sunscreen every day. The best sunblock for your skin may differ, but everyone needs to wear sunscreen. It’s one of the only skincare recommendations I give to every patient I see. Wearing sunscreen every day is the easiest way to prevent skin cancer, which can save your life. Sunscreen also helps to prevent sun damage that causes wrinkles and dark spots, keeping skin looking youthful and healthy. ” You can learn more in our blog debunking five common sunscreen myths.

Myth 1 – I Don’t Need to Wear Sunscreen on Cloudy Days

While cloud cover can ease the immediate, warming effects of direct sunlight, clouds don’t actually stop the sun’s ultraviolet (UVA and UVB) rays from damaging the skin. Dr. Marinaro says, “When it’s cold or cloudy outside, people often experience a false sense of security that they’re not receiving damaging exposure to the sun, but this just isn’t the case. Even if your skin doesn’t feel the heat of the sun, UV rays can still be doing damage.” Luckily, when it’s cold and cloudy outside, people are more likely to keep their skin protected by wearing clothes that cover skin, but it’s still important to apply a broad-spectrum sunscreen every day to areas that will be exposed to sunlight, including the face, neck, and hands. If you are balding or have a pronounced hairline that reveals your scalp, don’t forget to wear a hat or apply sunblock to protect this area from damage as well.

Myth 2 – High SPF Sunscreen Lasts All Day

According to Dr. Marinaro, “If you’re prone to sunburn or have very pale skin, you need to use a higher SPF factor sunscreen, but just because the sunscreen is more powerful, that doesn’t mean it lasts forever.” So, what exactly does that higher SPF mean? SPF is an acronym used to abbreviate Sun Protection Factor, which refers to a mathematical equation used to determine how effective sunblock and sunscreen are as well as how long they’ll last.

If you do the sun protection factor math, sunscreens with an SPF of 30 are typically formulated to block about 90 to 95% of UVB rays, and it takes 30 times longer for the sun to damage skin than it would without coverage. That means a person whose skin would usually be damaged after 10 minutes can wear an SPF 30 sunscreen for about five hours and maintain 90 to 95% protection from the sun’s damaging UVB rays.

By that math, sunscreens with SPF 50 should allow that same person who receives sun damage after 10 minutes to stay outside for eight hours. In theory, this means all-day wear. Dr. Marinaro says, “There are many reasons people need to reapply sunscreen frequently even if they’re using a high SPF product. It sounds reasonable to conclude SPF 50 means you can be out in the sun 50 times longer, but that amount of time changes for each individual and depends on the time of the year, time of day, and other variables. There is also a property of sunscreen called substantivity. Substantivity is the ability of a sunscreen to remain effective under the stress of prolonged exercise, sweating, swimming, and exposure to the sun. Even high SFP sunscreen gets oxidized by the sun which renders them less effective over time. It’s extremely difficult to pinpoint exactly how long sunscreen remains effective for each person. The more important difference between SPFs is that an SPF 50 sunscreen has to earn that designation by blocking 95 to 98% of UVB rays versus an SPF 30 that may only block 90%. However, the sunscreen’s SPF doesn’t determine how effective it is at blocking UVA rays, which can contribute to long-term damage like skin cancer and accelerated aging. That’s why we always encourage people to use a broad-spectrum sunscreen that’s effective against UVA and UVB rays and reapply at least every two hours.”

Myth 3 – I Have Dark Skin or Don’t Sunburn, so I Don’t Need Sunscreen

Some people, including those with dark skin tones, are less likely to burn when exposed to sunlight. Unfortunately, sunburn is just one of the damaging effects of exposure to the sun’s UVA/B rays. Even if your skin doesn’t burn, unprotected sun exposure still puts you at increased risk for skin cancer and accelerated signs of aging (wrinkles and age spots). No matter your skin tone or history with sunburns, you should still be using sunscreen every day.

Myth 4 – My Sunscreen is Waterproof, so I Don’t Have to Reapply

Even waterproof or water-resistant sunscreens need to be reapplied regularly. According to Dr. Marinaro, “Choosing a sunscreen or sunblock that is promoted as being waterproof or sweatproof is great if you’re going to be outdoors swimming or exercising, but that doesn’t mean the sun protection product lasts forever. You’ll still need to reapply the sunblock or sunscreen at least every two hours to ensure you maintain the optimal level of efficacy.”

Myth 5 – I Have a Vitamin D Deficiency, so I Shouldn’t Wear as Much Sunscreen

Vitamin D deficiency is actually very common for people over the age of 30. As we age, our bodies become less efficient at processing nutrients from the foods and beverages we consume as well as those vitamins that can be absorbed by the skin. Not long ago, many physicians prescribed increased sun exposure or even trips to the tanning bed to treat vitamin D deficiencies. Today, we understand that the risk for skin cancer far outweighs any potential benefits of receiving a boost in vitamin D through prolonged exposure to UV rays. Instead, most physicians recommend incorporating foods that are rich in vitamin D into the diet as well as taking a vitamin D supplement every day. If you do spend more time outdoors to promote a healthier level of vitamin D, you should still apply sunscreen.

Visit the Team at U.S. Dermatology Partners

If you’re interested in learning more about how to protect your skin from the sun’s damaging rays, you’re ready to make some changes in your skincare routine, or you’re concerned about a new lesion that may be indicative of a serious skin condition, U.S. Dermatology Partners is here to help. Our team of knowledgeable, board-certified dermatologists brings unique experiences, training, and skillsets to our practices, providing patients with a range of dermatology solutions to achieve, maintain, or restore healthy, beautiful skin. We’re here to help when you need us. Simply reach out using our easy, online contact form, and one of our team members will be in touch soon.

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