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Category: Safety Information

Beyond the Basics: Lesser-Known Facts for Effective Sunscreen Use

Sunscreen is an essential product for protecting our skin from the harmful effects of the sun's ultraviolet (UV) radiation. While many people are aware of the basics of sunscreen, such as its SPF (Sun Protection Factor) and the need for regular reapplication, here are some lesser-known facts about sunscreen: 

Sunscreen Expiration: Sunscreen has an expiration date. Most sunscreens are designed to remain stable and effective for about three years. After that, they may start to degrade and become less effective. Be sure to check the expiration date on your sunscreen bottle before using it. 

Shelf Life after Opening: Once opened, sunscreen can lose its effectiveness over time due to exposure to air and bacteria. It's generally recommended to use opened sunscreen within one year, even if the expiration date hasn't been reached. 

Broad-Spectrum Protection: Not all sunscreens offer broad-spectrum protection. Broad-spectrum sunscreen protects against both UVA and UVB rays. UVA rays contribute to skin aging, while UVB rays are responsible for sunburns. When purchasing sunscreen, look for products labeled "broad-spectrum" to ensure you're getting protection against both types of rays. 

Application Quantity: Most people don't apply enough sunscreen. The general guideline is to use approximately one ounce (about a shot glass full) of sunscreen for your entire body. Studies have shown that people tend to use only 25-50% of the recommended amount, significantly reducing the level of protection. 

SPF and Sunburn Protection: SPF measures protection against UVB rays, not UVA rays. The SPF number indicates the amount of UVB protection the sunscreen provides. For example, SPF 30 blocks about 97% of UVB rays, while SPF 50 blocks about 98%. However, it's important to note that SPF does not directly measure protection against UVA rays, which can still cause skin damage. 

Waterproof vs. Water-Resistant: The terms "waterproof" and "sweatproof" are misleading. No sunscreen is entirely waterproof or sweatproof. The term "water-resistant" means that the sunscreen retains its SPF protection for a specific amount of time (usually 40 or 80 minutes) while swimming or sweating. Reapply sunscreen after that time to maintain protection. 

Sunscreen and Vitamin D: Using sunscreen does not eliminate your body's ability to produce vitamin D. While sunscreen reduces the skin's ability to produce vitamin D from sunlight, most people can still get enough vitamin D through their diet and incidental sun exposure during outdoor activities. 

Sunscreen and Cloudy Days: UV rays can still penetrate clouds, so it's important to wear sunscreen even on cloudy days. Up to 80% of UV rays can pass through clouds, contributing to skin damage. 

Remember, sunscreen should be just one part of your sun protection routine. Combine it with seeking shade, wearing protective clothing, and using sunglasses to protect your skin and eyes from the sun's harmful rays. Learn more about dermatology services at CaroMont Health.