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Sunscreen is found in various products that you put on your skin to protect it from the sun’s UV rays. But it’s important to know it’s called sunscreen for a reason and there is no such thing as sunblock. Sunscreen is just a filter – it does not block all UV rays.
Sunscreen needs to be reapplied at least every 2 hours to maintain protection. Sunscreen can wash off when you sweat or swim or when you dry off with a towel, so it might need to be reapplied more often. Some people may find they need to reapply sunscreen more often regardless of the activity they’re doing outside. Always be sure to read the label.
Even if you use a sunscreen with a very high SPF, this doesn’t mean you can stay out in the sun longer, use less sunscreen, or apply it less often. Again, always be sure to read the label.
Always follow the label directions for applying and re-applying sunscreen products. Most experts recommend applying sunscreen generously whether it’s your first time using it for the day or you’re re-applying it after a length of time.
When putting sunscreen on:
Ideally, sunscreen should be applied generously. You might see instructions saying to apply liberally or generously. Or you might see a recommended amount to use. It’s important to use enough to have full coverage of arms, legs, neck, face, and any other areas that are exposed to the sun.
Sunscreens are available in many forms, including lotions, creams, ointments, gels, sprays, wipes, and lip balms. Some cosmetics, such as moisturizers, lipsticks, foundations, and other makeups are also considered sunscreen products if they have sunscreen as an ingredient. It’s important to remember that no sunscreen protects you completely.
When choosing a sunscreen product, be sure to read the label. It’s best to use sunscreen with broad spectrum protection (against both UVA and UVB rays) and with sun protection factor (SPF) values of 30 or higher.
Some sunscreen products can irritate the skin. Some labels may provide information about how to test for skin irritation or sensitivity. If your skin becomes irritated, contact your doctor or a dermatologist for ideas about which type or brand might be best for you.
The SPF number is the level of protection the sunscreen provides against UVB rays, which are the main cause of sunburn.
When applying sunscreen correctly, you get the equivalent of 1 minute of UVB rays for a certain about of time you spend in the sun. The amount of time is based on the SPF level of the product. For example, a sunscreen with SPF 30 gives the equivalent of 1 minute of UVB rays for each 30 minutes you spend in the sun. This means 1 hour in the sun wearing SPF 30 sunscreen is the same as spending 2 minutes in the sun totally unprotected. Higher SPF numbers do mean more protection, but the higher you go, the smaller the difference becomes.
Sunscreen products can only be labeled “broad spectrum” if they have been tested and shown to protect against both UVA and UVB rays. Sunscreens that help protect against UVA rays might include avobenzone (Parsol 1789), zinc oxide, and titanium dioxide.
Only broad spectrum sunscreen products with an SPF of 15 or higher can state that they help protect against skin cancer and early skin aging if used as directed with other sun protection measures.
Sunscreens cannot be labeled as “waterproof” or “sweatproof” because these terms can be misleading. Sunscreens can claim to be “water resistant,” but they have to state whether they protect the skin for 40 or 80 minutes of swimming or sweating, based on testing.
Check the expiration date on the sunscreen to be sure it’s still effective. Most sunscreen products are good for at least 2 to 3 years, but you may need to shake the bottle to remix the sunscreen ingredients. Sunscreens that have been exposed to heat for long periods, such as if they were kept in a glove box or car trunk through the summer, may be less effective.
The US Food and Drug Administration (FDA) is required to monitor sunscreen since it’s considered a cosmetic. The FDA has very high standards during this process that are based on scientific research to be sure the product is safe for public use. The FDA looks at the ingredients in a sunscreen and how it is made to determine if the product is safe and effective. If it is, the sunscreen is considered GRASE (generally safe and effective).
Currently, the FDA has not reported that any sunscreen ingredients used in the US are harmful to a person’s health. However, the FDA has recommended more research be done on certain ingredients that are often used in sunscreen products. The ingredients commonly used in the US that the FDA lists as needing more research are: ensulizole, octisalate, homosalate, octocrylene, octinoxate, oxybenzone, and avobenzone. You can read more about these ingredients at fda.gov.
Expert organizations consider sunscreen a safe, vital tool in the prevention of skin cancer. Along with the FDA, the American Cancer Society (快猫短视频) and the American Academy of Dermatology Association (AAD) continue to include using sunscreen with SPF 30 or higher (along with wearing protective clothing, hats, and sunglasses) to protect your skin from harmful UV rays.
Not all sunscreen stays on your skin when it is applied. Swimming, showering, and sweating can cause sunscreen to wash off and go into waterways. Scientists have found that certain chemicals in some sunscreen products can harm coral reefs and other organisms in bodies of water.
Mineral sunscreen is a good option since it does not use the types of chemicals that can be harmful to marine life. Additionally, wearing UV protective clothing is a good option for protecting your skin when there is concern about sunscreen ingredients being harmful during water activities.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
American Academy of Dermatology (AAD). Is Sunscreen Safe? Accessed at https://www.aad.org/public/everyday-care/sun-protection/shade-clothing-sunscreen/is-sunscreen-safe on June 26, 2024.
National Academies of Science, Engineering, Medicine (NASEM). Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health. 2022. Accessed at https://nap.nationalacademies.org/catalog/26381/review-of-fate-exposure-and-effects-of-sunscreens-in-aquatic-environments-and-implications-for-sunscreen-usage-and-human-health on June 26, 2024.
National Ocean Service. Skincare Chemicals and Coral Reefs. 2013. Accessed at https://oceanservice.noaa.gov/news/sunscreen-corals.htm on June 26, 2024.
US Food and Drug Administration (FDA). FDA Takes Steps Aimed at Improving Quality, Safety and Efficacy of Sunscreens. 2021. Accessed at https://www.fda.gov/news-events/press-announcements/fda-takes-steps-aimed-improving-quality-safety-and-efficacy-sunscreens on June 26, 2024.
US Food and Drug Administration (FDA). Sunscreen: How to Help PRotect Your Skin from the Sun. Accessed at https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun on June 26, 2024.
Last Revised: June 26, 2024
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