SPF is a crucial tool for skin protection, but its effectiveness hinges on correct usage, according to skincare scientist Clare O'Connor. She highlights that many individuals make common mistakes that compromise their sun protection, even when using sunscreen daily.
Choosing the Right SPF
O'Connor emphasizes that the choice of SPF should align with individual skin type and planned outdoor activities. "If you're fair and you're going to be outdoors all day, then you're probably going to need to start with an SPF 50. But if you're just popping into the garden for half an hour or doing a bit of gardening, an SPF 15 may be perfectly adequate," she explains. Using an SPF that is too low for one's skin type means that even frequent reapplication will not prevent sunburn.
Understanding SPF Ratings
A significant misconception is that SPF numbers indicate total sun protection. O'Connor clarifies that SPF ratings only address protection against sunburn and do not reflect the level of UVA protection offered. UVA rays penetrate deeper into the skin, contributing to long-term damage such as premature aging. She advises looking for a UVA symbol within a circle or products with a high UVA rating.
Correct Application Amounts
The quantity of sunscreen applied is critical to achieving the protection advertised on the label. O'Connor's "two-finger rule" suggests squeezing sunscreen along the length of the index and middle fingers for adequate facial coverage, ensuring an even film on the skin. For the body, a "two-pound-coin-sized blob for each limb or roughly a shot glass full to cover the entire body" is recommended.
Areas Often Missed
Sunscreen protection gradually diminishes throughout the day, and certain areas are frequently overlooked during application. According to research cited by O'Connor, the ears (15.7%), scalp (15.1%), and back of the neck (12.7%) are the most commonly missed spots, despite being highly exposed. These areas are also prone to sunscreen wearing away due to clothing friction and sweat.
Reapplication and Makeup
Reapplication is vital every two hours when exposed to sunlight. For those wearing makeup, O'Connor suggests a method to reapply sunscreen without disrupting their makeup. Instead of rubbing, she recommends dabbing sunscreen onto the skin using a makeup sponge or brush to recreate an even protective layer.
Sunscreen Longevity and Storage
Sunscreen can degrade if exposed to high temperatures. O'Connor warns that leaving sunscreen in a hot car can cause it to split. While beach bags are less of a concern as products are tested for temperature changes, sunscreen that has separated into an oily liquid or appears curdled should be replaced. If it retains a creamy consistency and normal smell, it may still be effective.
Mineral vs. Chemical Formulas
O'Connor debunks the myth that mineral sunscreens are inherently more natural or gentler. She states, "People talk about chemical versus non-chemical sunscreens, but they're all chemicals. Mineral sunscreens aren't more natural, and they're not necessarily less irritating." While mineral formulas can benefit individuals with conditions like rosacea, they may leave a white cast. Ultimately, O'Connor believes the best sunscreen is the one a person enjoys using, as this increases the likelihood of proper and regular application.
Formats: Sprays, Sticks, and Lotions
All sunscreen formats, including lotions, sprays, and sticks, undergo the same testing. However, misuse can affect their efficacy. O'Connor notes that sprays can be misused if users don't apply enough or rub them into the skin, failing to achieve the necessary layer of protection. Sticks are useful for targeted areas like the nose and lips due to their thick application. While SPF top-up sprays have gained popularity, O'Connor expresses skepticism about their standalone effectiveness, recommending them only as a supplement to a base layer of sunscreen.