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By Talia Emery, M.D.
Very few of us are actually using sunscreen properly. Chances are you’re using too little, too infrequently. Why is this? Based on what I see in my practice, most people don’t know how to choose a sunscreen that’s right for them. There are questions about which SPF is ideal, whether a chemical or physical sunscreen is best, and how to find a product that feels good and isn’t irritating. Let’s cover the basics and get you ready for a safe summer.
For the best protection, you need to apply a broad-spectrum sunscreen with an SPF 30 or greater every 2 hours. A broad-spectrum sunscreen protects against both types of ultraviolet rays: UVA rays, responsible for premature aging of the skin, and UVB rays, responsible for sunburns.
A sunscreen’s SPF—Sun Protection Factor—measures protection against UVB rays. The SPF indicates how long you can stay in the sun without burning. It’s a multiple of the time required to burn. For example, if your unprotected skin would turn red in 10 minutes, an SPF 15 would protect your skin for 15 times as long, or 150 minutes. However, most sunscreens break down or wear off within 2 to 4 hours of application. Therefore, to achieve the duration of protection indicated by the SPF, sunscreen must be reapplied often.
Currently, there is no standardized rating system for UVA protection, but sunscreens that are effective against UVA rays are clearly marked. It’s important to use these sunscreens in your car and in some cases even indoors, because windows don’t block those aging UVA rays. Ever wonder why the left side of your face has a few more wrinkles? Those UVA rays have been sneaking in your driver’s side window for years!
Both chemical and physical sunscreens can be effective. Most of us have been using chemical sunscreens for decades. Typically lotions, creams or sprays, they should be applied 30 minutes prior to sun exposure. They absorb into the skin and work by filtering the sun’s harmful rays. Physical sunscreens have emerged over the past decade and act as a barrier for the skin, blocking and reflecting ultraviolet rays. Absorption isn’t required for physical sunscreens, so they can be applied immediately prior to sun exposure. Popular forms are lotions, creams, and the powder of mineral makeup.
From my experience, chemical sunscreens are more often associated with adverse skin reactions while physical sunscreens feel “heavier” on the skin. Fortunately, top skin care companies have sunscreen formulations for a variety of skin types, so everyone can find something that works for them.
Everyone should have a daily sunscreen. All exposed areas of the body should be covered with a sunscreen applied every 2 hours or immediately after swimming or perspiring. Lips are also prone to sunburn, so wear and reapply lip protection with a high SPF. And even a daily moisturizer or mineral make-up with sunscreen needs to be reapplied.
Remember, you’re likely using too little sunscreen, too infrequently. Enjoy your summer and don’t get burned!
Fun facts to share at your next pool party: SPF is a multiplier of burn time; UVA = Aging, UVB = Burning; windows block UVB, but not UVA; chemical sunscreens filter, physical sunscreens block.