The sun, although glorious, is also responsible for most of the loathsome wrinkles, age spots, and skin cancers. Then why, oh why, are only 14 percent of women wearing sunscreen?More than 2 million people in the United States are diagnosed with skin cancer each year, making it the most common form of cancer. It is so unfortunate that the most common type of cancer is also largely preventable. Research estimates that 90 percent of non-melanoma skin cancers and 65 percent of melanoma skin cancers are associated with exposure to ultraviolet (UV) radiation from the sun. And, according to the American Academy of Dermatology using sunscreen can reduce the risk by 50 percent.
The two types of UV radiation that affect the skin—UVA and UVB—have both been linked to skin cancer and a weakening of the immune system. They also largely responsible for the premature aging of the skin and color changes (i.e. wrinkles!). UVA rays are not absorbed by the ozone layer around the earth, and thus penetrate deep into the skin causing premature aging. Up to 90 percent of the visible skin changes commonly attributed to aging are caused by sun exposure (think UVA = Aging). On the other hand, UVB rays are partially absorbed by the ozone layer. They mostly affect the surface of the skin and are the primary cause of sunburn (UVB= Burn).
So how does this science translate into our daily use of sunscreen? Sunscreens protect your skin by absorbing and/or reflecting UVA and UVB rays.There are two types of sunscreens: chemical and physical. Broad-spectrum sunscreens often contain a number of chemical ingredients that absorb UVA and UVB radiation. Many sunscreens contain UVA-absorbing avobenzone or a benzophenone (such as dioxybenzone, oxybenzone, or sulisobenzone), in addition to UVB-absorbing chemical ingredients (some of which also contribute to UVA protection). The physical sunscreens have compounds of titanium dioxide and zinc oxide which reflect, scatter, and absorb both UVA and UVB rays. And through new technology, the particle sizes of zinc oxide and titanium dioxide have been reduced, making them more transparent without losing their ability to screen UV (no more white lifeguard nose).
In addition to using a broad-spectrum sunscreen, the strength is also important. The FDA requires that all sunscreens contain a Sun Protection Factor (SPF) label, what type of UV protection a sunscreen offers, and what a sunscreen can do (and by the way, companies can no longer market “waterproof”; there is no such thing). The SPF reveals the relative amount of sunburn protection that a sunscreen can provide an average user when used correctly. Sunscreens with an SPF of at least 15 are recommended by the FDA, but the American Academy of Dermatologist (AAD) recommends broad-spectrum, water resistant sunscreens with an SPF of at least 30. You should be aware that an SPF of 30 is not twice as protective as an SPF of 15. Rather, when properly used, an SPF of 15 protects the skin from 93 percent of UVB radiation, and an SPF 30 sunscreen provides 97 percent protection (see graph). When contemplating your free-market choices of sunscreen, bear in mind that a higher number SPF may block slightly more (about 1 percent) of the sun’s rays than SPF 30, but no sunscreen can block 100 percent of the sun’s UV rays. Additionally, there is insufficient data to show they provider greater protection according to the FDA, which has proposed prohibiting the sale of formulas with an SPF over 50.
Even if you are buying the proper sunscreen, according to recent surveys most people are confused about their proper use. Twenty-nine percent of people using sunscreen waited until they were in the sun to slather it on. But in order to get full protection, the AAD states that sunscreen needs to be applied 15 to 30 minutes before sun exposure and then should be reapplied every two hours or after immediately swimming or sweating. It takes about one ounce of sunscreen, or about two tablespoonfuls, to cover your face and all exposed areas of your body. Most people only use half that much.