Proper application of sunscreen is crucial for effective skin protection, according to skincare scientist Clare O'Connor. Many individuals make common mistakes that can reduce the efficacy of sunscreen, leaving them less protected than they believe.
One significant misconception is that the SPF number alone indicates total sun protection. SPF primarily measures protection against sunburn, not against UVA rays, which penetrate deeper into the skin and contribute to long-term damage like premature aging. O'Connor advises looking for a UVA symbol within a circle or products with a high UVA rating.
The amount of sunscreen applied is another critical factor. The quantity needed to achieve the advertised protection is often more than people typically use. For the face, O'Connor recommends the "two-finger rule," squeezing sunscreen along the length of the index and middle fingers to ensure an even film on the skin. For the body, a "shot glass full" or a "two-pound-coin-sized blob for each limb" is suggested.
Areas frequently missed during application, such as the ears, scalp, and the back of the neck, are highly exposed and prone to sunscreen wearing off due to sweat and friction from clothing. O'Connor emphasizes the need to reapply sunscreen every two hours, especially during extended periods outdoors.
Reapplying sunscreen without disrupting makeup can be a challenge. O'Connor suggests using a makeup sponge or brush to dab sunscreen onto the skin rather than rubbing it, which helps maintain makeup coverage while ensuring protection.
Sunscreen's effectiveness can also be compromised by improper storage. Leaving sunscreen in hot environments, like a car, can cause it to separate. While sunscreens are tested for temperature changes, O'Connor advises replacing products that have separated into an oily liquid or look curdled. If the product still appears creamy and smells normal, it is likely still effective.
The distinction between mineral and chemical sunscreens is often misunderstood. O'Connor clarifies that all sunscreens are chemical-based, and mineral formulas are not inherently more natural or less irritating, though they may be suitable for certain skin conditions. The best sunscreen, she notes, is the one a person enjoys using and will therefore apply correctly and consistently.
Sunscreen formats like sprays and sticks have varying usability. Sprays can be effective but are often misused, with users not applying enough to create an adequate protective layer. Sticks are useful for targeted areas like the nose and lips. O'Connor expressed skepticism about the effectiveness of "top-up" spray products on their own, recommending them only as a supplement to a primary sunscreen application.
Several products were highlighted for specific needs: La Roche-Posay's SPF 50 offers high UVA and UVB protection for all skin types. No7's Prime Forever SPF provides a seamless base for makeup. Merit's tinted SPF offers coverage and SPF 50 protection. Dr. Sam's non-comedogenic sunscreen is recommended for blemish-prone skin. A Korean sunscreen enriched with rice extract and vitamin B5 is suggested for dry skin, while an ultra-light fluid is recommended for oily complexions. Ultra Violette's Bejewelled lip product provides sun protection for lips, and a gel-serum texture sunscreen offers an invisible finish without a white cast.