Facts about Sunscreen
What is an SPF?
The Sun Protection Factor (SPF) displayed on the sunscreen label ranges from 2 to as high as 50 and refers to the product’s ability to screen or block out the sun’s harmful rays. For example, if you use a sunscreen with an SPF 15, you can be in the sun 15 times longer that you can without sunscreen before burning. Consumers need to be aware that SPF protection does not increase proportionally with an increased SPF number. While an SPF of 2 will absorb 50% of ultraviolet radiation, an SPF of 15 absorbs 93% and an SPF of 34 absorbs 97%.
How do you select a sunscreen?
With so many brands of sunscreen available, selecting the right sunscreen can be difficult. These tips may help you in making your selection:
Dermatologists strongly recommend using a sunscreen with an SPF 15 or greater year-round for all skin types. If you are fair-skinned and sunburn easily, you may want to select a sunscreen with a higher SPF to provide additional protection. Using a cream, oil or lotion is a matter of personal choice, but keep in mind that most oils do not contain sufficient amounts of sunscreen and usually have an SPF of less than 2. All sunscreens need to be reapplied, so follow the guidelines written on the sunscreen bottle. Gel sunscreens tend to sweat off and, therefore, need to be reapplied more frequently. Remember, expensive sunscreens are not necessarily of better quality.
Choose a “broad-spectrum” sunscreen that protects against UVB and UVA radiation. PABA, or para-aminobenzoic acid, was one of the original ultraviolet B (UVB) protecting ingredients in sunscreens. However, some people’s skin is sensitive to PABA, and it also can cause staining of clothing. Today, PABA has been refined and newer ingredients called PABA esters (such as glycerol PABA, padimate A and padimate O) can be found in sunscreens. PABA and PABA esters only protect against UVB radiation, the sun’s burning rays that are the primary cause of sunburn and skin cancer. Also look for other UVB absorbers listed in the ingredients such as salicylates and cinnamates.
You should look for a sunscreen that also protects against ultraviolet A (UVA) radiation, those rays that penetrate deeper into the skin and are the culprits in premature aging and wrinkling of the skin. UVA-screening chemicals include oxybensone, sulisobenzone and Parsol 1789, also called avobenzone. NOTE: The SPF number on sunscreens only reflects the product’s ability to screen UVB rays. At present there is no FDA-approved rating system that measures UVA protection levels.
Look for a sunscreen that is “waterproof” or “water-resistant,” especially if you participate in outdoor physical activity.
Is there a difference between “waterproof” and “water-resistant?”
How well the sunscreen stays on the skin after swimming, bathing or perspiring is just as important as the SPF level. The FDA considers a product “water-resistant” if it maintains its SPF level after 40 minutes of water exposure. A product is considered “waterproof” if it maintains its SPF level following 80 minutes of exposure to water. If you participate in outdoor recreational activities including swimming, you may want to choose a waterproof sunscreen.
What is the difference between sunscreen and sunblock?
Sunscreens can be classified into two major types: chemical and physical. Chemical sunscreens contain special ingredients that act as filters and reduce ultraviolet radiation penetration to the skin. These sunscreens often are colorless and maintain a thin visible film on the skin. These sunscreens usually contain UVB absorbing chemicals and more recently contain UVA absorbers as well.
Physical Sunscreens, most often referred to as sunblocks, are products containing ingredients such a titanium dioxide and zinc oxide which physically block ultraviolet radiation (UVR). Sunblocks provide broad protection against both UVB and UVA light. They can be cosmetically unacceptable to many people, because they are often messy, visible and do not easily wash off. However, some new zinc oxide products are available in brightly colored preparations which are popular with young people. The amount of sun protection these sunblocks provide, while potentially high, cannot be quantified in the same manner as sunscreen SPFs. Physical sunscreen is recommended for individuals who have unusual sensitivity to UVR. Most recently on the sun protection scene is sun-protective clothing designed to block UVA and UVB radiation. The effective SPF is greater that 30.
When should you use a sunscreen?
Sunscreens should be used daily if you are going to be in the sun for more than 20 minutes. Most people will receive this amount of sun exposure while performing routine activities. They can be applied under makeup. There are many cosmetic products available today that contain sunscreens for daily use because sun protection is the principal means of preventing premature aging and skin cancer. Sunscreen used on a regular basis actually allows some repair of damaged skin. Because the sun’s reflective powers are great – 17 percent on sand and 80 percent on snow – don’t reserve the use of these products for only sunny summer days. Even on a cloudy day 80 percent of the sun’s ultraviolet rays pass through the clouds. Skiers beware, ultraviolet radiation increases 4 percent for every 1,000-foot increase in altitude.How much sunscreen should you use and how often should you apply it? You should apply sunscreen to your dry skin 30 minutes BEFORE going outdoors. Pay particular attention to your face, ears, hands and arms. Apply sunscreen liberally using one ounce to completely cover your body. Be careful to cover exposed areas, a missed spot could mean a patchy, painful sunburn. Lips get sunburned too, so apply a lip balm that contains sunscreen with SPF 15 or higher. Sunscreens should be applied in the morning and reapplied after swimming or perspiring heavily. Remember, waterproof sunscreen begins losing effectiveness after 80 minutes in the water, so reapply sunscreen before this time, especially if you have towel-dried for maximum protection.
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