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Debunking Six Sun Care Myths

Photo: Courtesy of the National Cancer Institute

Dr. Muneeb Shah

Dermatology Resident Physician

Everyone loves to talk about their skin care routines, but when it comes to taking care of your skin sometimes it’s hard to differentiate between truth and myth. Let’s unravel the truth behind some of the most persistent misconceptions about sun protection and skin care.  

1. To get the greatest sun protection, I should buy the highest SPF available

Higher SPF does provide more sun protection, but it becomes marginal as the SPF number climbs above 30, depending on how you look at it. SPF 30 blocks 97% of UVB light and SPF 50 blocks 98% of UVB light. The difference appears to only be 1% depending on how you look at it, but you can also look at it like SPF 30 lets in 50% more UVB light. Also, we know that most people don’t apply enough sunscreen based on the recommended volume and higher SPF levels can account for the discrepancy to some degree. 

2. If my makeup has SPF protection, I don’t need to wear sunscreen on my face

This one is both true and false. If your make-up says that it’s SPF 30, then it’s SPF 30. But the key is that you need to apply enough sunscreen to meet the lab testing standards that they used to come up with that number. This is equal to about 2mg/cm squared of sunscreen. For most people, this is about two finger-lengths of sunscreen to cover the face, neck, and ears. The problem is that when people use a moisturizer with SPF or a foundation with SPF, they often don’t apply enough of it to meet the SPF level on the label. 

3. If it’s cloudy or cold, I don’t need to wear sunscreen

When it’s cloudy, we still get UV radiation. We also still get UV radiation in the winter and when we are in our cars. However, the amount of UV exposure does change throughout the year and you can look at the “UV index” to see how harsh the sun is on a particular day. That being said, I recommend making it a habit to wear sunscreen every single day, regardless of UV index or whether you plan to be outside for an extended period of time. 

4. If I get water-proof sunscreen, I won’t need to reapply

False. Sunscreens are formulated to be reapplied every two hours. They do have some effect after the two hours but the UV protection drops throughout the day if it’s not reapplied. 

5. If I have darker skin, I don’t need to worry about sunscreen because I’m protected by melanin

Melanin does protect against the sun to some extent, but the sun causes DNA damage regardless of skin tone. We see this in studies where they evaluate “UV-signature mutations,” which are DNA mutations that occur after sunlight exposure. The risk of skin cancer is certainly lower in people with deeper skin tones, however, one of the issues that is more prevalent with more melanin is hyperpigmentation and melasma.

Hyperpigmentation, which is often caused or exacerbated by the sun, is one of the most common complaints from people with darker skin tones and it can be very difficult to treat.

6. You only need to wear sunscreen while staying outdoors for a long period of time

As I was saying earlier, you really should make it a habit to wear sunscreen every single day. We know that even passive sunlight exposure can increase the risk of skin cancer and exacerbate photo-aging. Also, UVA radiation, the wavelength most responsible for aging, can actually penetrate window glass.

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