Sun & Skin News

Ask the Expert: How Often Do I Need to Reapply Sunscreen If I’m Indoors All Day?

By Skin Cancer Foundation • July 14, 2021
sun lit living room

Sunscreen is an important part of a complete sun protection strategy, and it’s essential to reapply throughout the day to ensure you’re getting the most out of the product you choose. Generally, I recommend reapplying every two hours. Be sure to use enough product — about one ounce for your entire body — to achieve the full broad-spectrum protection of the sunscreen.

Even if you’re inside all day, wearing sunscreen on any exposed skin is still important. Most ultraviolet (UV) rays can penetrate glass, so if you’re working or relaxing near a window, you’re receiving sun exposure. That said, if you’re spending all day inside and you’re not near a window, there’s no need to reapply as frequently. You can reapply every four to six hours. Just remember that sun damage is cumulative, so even if you’re only exposed for a short time, it’s important to have protection.

About the Expert:

Elizabeth Richard, MD profile pictureElisabeth G. Richard, MD is a board-certified dermatologist practicing in Lutherville, Maryland. She is an assistant professor of dermatology at Johns Hopkins University School of Medicine and a member of The Skin Cancer Foundation’s Photobiology Committee.

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