Sun & Skin News

Reapply on the Fourth of July

By Ali Venosa • June 9, 2021
reapply sunsccreen

We’re gearing up for the holiday and doing our best to ensure that all our friends enjoy a sun-safe fourth! Regular readers of our blog should know our sun safety tips by heart, but there’s one that we know people have trouble with: remembering to reapply sunscreen.

Why Reapply?

Unlike with a hat or sunglasses, sunscreen’s effectiveness against ultraviolet (UV) rays doesn’t remain constant.

A quick refresher: A sunscreen’s Sun Protection Factor (SPF) measures how well the product will protect you from the sun’s UVB rays— the type of UV that is primarily responsible for sunburn. For example, if your unprotected skin begins to burn within 20 minutes of sun exposure, applying an SPF 15 sunscreen would theoretically keep your skin from burning 15 times longer: 300 minutes, or about five hours. But experts agree that no sunscreen can remain completely effective for that long, as active ingredients degrade over time. This is why dermatologists and The Skin Cancer Foundation recommend reapplying sunscreen at least every two hours, regardless of the formula, SPF, or brand of the product.

Furthermore, even if your sunscreen has a high SPF, you have to make sure that it provides broad-spectrum protection, meaning that it protects well against UVA rays as well as UVB. Burning isn’t everything— without burning your skin, UVA rays cause premature skin aging and contribute to skin cancer, so you need a good broad-spectrum sunscreen even if you tend never to burn.

Get the Most Out of Your Sunscreen

Now you know why it’s so important to reapply, but are you confident you’re applying your sunscreen so you get the most out of it? Here are a few tips to keep in mind when you’re slathering up: 

  • Apply Sunscreen 30 Minutes Before Going Outside. This is particularly important if you’re using a chemical sunscreen, because it takes time for the skin to absorb the chemical filters that help protect you. Regardless of the type of sunscreen you use, applying sunscreen well before you go outside is a good habit to get into, so you don’t end up being exposed to the sun before remembering to apply sunscreen.
  • Use the Right Amount. Studies have shown that many people apply only half (or even a quarter!) of the amount of sunscreen they should be using for full effectiveness. You should go through sunscreen bottles pretty quickly if you’re applying the correct amount—an ounce, or about a shot glass full, should be sufficient for the entire body. And you should be reapplying the same amount throughout the day.
  • Apply it Everywhere. Speaking of the entire body, that’s where sunscreen should be applied! It’s easy to forget about spots like the top of your ears or the back of your neck, but those spots are common places for skin cancers. It’s especially important to liberally apply sunscreen to the face, since the skin there is thinner, and often highly exposed to UV rays. Finally, apply sunscreen before donning your clothes or swimsuit; otherwise, it’s easy to miss a spot at the edges of the clothing.
  • Reapply Immediately After Swimming or Sweating. Even if you put sunscreen on right before you jump in the pool then dry off, you should reapply right away. No sunscreen is truly waterproof — though there are great water-resistant formulas available — and toweling off means you’re wiping away the sun protection afforded by the product you used.
  • Don’t Rely on Sunscreen for Complete Protection. Sunscreen is just one part of an effective sun protection plan. It’s an important one, but no method alone is foolproof. That’s why The Skin Cancer Foundation recommends seeking shade and covering up with hats, sunglasses and clothing in addition to daily sunscreen use.
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