You heard it here first (well, probably not, but it’s still important): Unprotected sun exposure is the most preventable risk factor for skin cancer. At today’s rate (roughly 3.5 million new cases every year), one in five of us will develop skin cancer in our lifetime. It’s also the most preventable cause of what we know as aging skin-wrinkles, lost elasticity and firmness, uneven texture
Sunlight comprises three types of ultraviolet (UV) radiation, two of which are important here: ultraviolet A (UVA) and ultraviolet B (UVB). While overexposure to either can lead to skin cancer, each has its own special way of damaging your skin:
Today’s sunscreen ingredients fall into two types-chemical and physical-which can be used individually or combined in a single product. Chemical sunscreens are active drug ingredients that absorb, scatter or reflect UV light, reducing its ability to penetrate the skin. Those that fight both UVA and UVB rays are known as broad-spectrum (or full-spectrum) sunscreens. Physical agents, known as sun blocks, physically block UV radiation (by definition, a sunblock provides broad-spectrum protection).
Broad-spectrum chemical sunscreens include encamsule (Meroxyl SX), avobenzone (Parsol 1798), oxybenzone and retinyl palmitate. Physical sunblocks include titanium dioxide and zinc oxide.
Sunscreens, which are regulated as over-the-counter (OTC) drugs by the US Food and Drug Administration (FDA), must carry a label statement that includes the product’s SPF, or sun protection factor. SPF typically ranges from 2 to 50, although some products boast an SPF as high as 100 (good if you’re hitting the beach on Mercury, apparently). The rating applies to the product’s ability to block UVB rays (there’s no rating for a product’s effectiveness against UVA rays); it’s an estimate of time you could spend in the sun before burning with that sunscreen on your skin compared to the time it would take to burn with no sunscreen on. Thus, an SPF of 15 should give you 15 times more sun time than you’d have if you were bare-skinned.
However, SPF protection doesn’t increase proportionally with the numbers – meaning 30 doesn’t deliver twice the protection of 15. A sunscreen with an SPF of 15 blocks about 94% of UVB rays, while SPF 30 blocks 97% and SPF 45 blocks about 98%. Some experts caution against using sunscreens with sky-high SPFs, in part because they tend to give consumers a false sense of security. Most dermatologists recommend products with an SPF of 30 or thereabouts.
Even sunscreen with an astronomical SPF won’t help you if you don’t apply it properly. Experts advise slathering it on – about an ounce, or what would fill a shot glass full or the palm of your hand- for your body, plus about a half-teaspoon for your face and neck. Research shows that less than half of us use the recommended amount, meaning we’re getting far less protection that we think we are (as little as 10% of the label’s SPF if we really skimp on application).
For the best protection, look for sunscreen labeled â€œwater resistantâ€ (according to the FDA, water-resistant sunscreen should stay effective after 40 minutes in the water; â€œvery water-resistantâ€ products should stick around for 80 minutes). Note that no sunscreen is completely waterproof, and manufacturers can no longer label products as such.
When applying sunscreen, the most common mistake is carelessness: Pay attention and you won’t miss the tops of your feet or the back of your neck. Apply the lotion directly onto your skin and rub it in with your fingertips (squirting it into your hands and then rubbing them together before applying means most of the sunscreen will stay on your palms, which are probably the least important place on your body to put sunscreen).
Be sure to apply sunscreen at least 15 minutes before you need it (that’s how long it takes to fully absorb and dry on your skin). Reapply at least every two hours-more often if you’re sweating a lot or are in and out of the water.