Monday, December 17, 2012
By mid-December 2012, sunscreen products on store shelves in the United States must meet stricter labeling regulations. Dr. Wang answers key questions on this topic.
For many years, the US Food and Drug Administration required that sunscreens sold in the United States indicate the extent to which the products protect consumers from sunburn-causing ultraviolet B (UVB) radiation, noted through a sun protection factor (SPF) value designated on the label.
On December 17, that changes. Under new labeling requirements, all but a handful of manufacturers claiming that their product provides a broad-spectrum SPF of 15 or higher will have to demonstrate its effectiveness in shielding people from the sun’s longer-wavelength ultraviolet A (UVA) radiation as well. Though UVA radiation is less likely than UVB radiation to cause sunburn, it has been linked to skin cancer and early skin aging.
In an interview, skin cancer expert Steven Wang, head of the dermatology section at Memorial Sloan Kettering Basking Ridge, in New Jersey, explains these changes and what they might mean to the general public.
What is sunscreen, and why should people use it?
Sunscreen is an over-the-counter medicine sold in the form of lotions, ointments, gels, and other mediums such as sprays to protect skin from ultraviolet (UV) radiation emitted by sunlight. An estimated 90 percent of the nation’s 3.5 million cases of skin cancer diagnosed each year are caused by exposure to the sun’s UV radiation. When used in conjunction with other sun protection measures, sunscreen can decrease the risk of skin cancer and prevent wrinkles, freckles, age spots, spider veins, and other signs of aging caused by the sun.Back to top
What does a sunscreen’s SPF really mean?
SPF is a standard way to measure the degree of protection that a sunscreen provides. To test for SPF, individuals in a controlled laboratory environment have a part of the body (usually the back) exposed to UV light. Initially this is done without sunscreen applied, to establish the smallest UV dose that produces visible redness of the skin with clearly defined borders at 16 to 24 hours following UV exposure. A repeat measurement is then performed to determine the smallest UV dose producing skin redness with sunscreen applied. The SPF value is the ratio of the UV dose producing redness on unprotected skin to the dose producing redness on sunscreen-protected skin.Back to top
What is changing with the new sunscreen regulations?
For the first time, the degree of a product’s protection from UVA as well as UVB light will be measured and integrated into the label indications. The measurement of UVA protection will be related to a product’s ability to shield the skin from a particular wavelength of UVA rays — greater than 370 nanometers. Only the products that protect against these wavelengths will be allowed to claim that they provide broad-spectrum protection.
In addition, products will no longer be allowed to designate themselves as “sunblock,” which I think is good because the term overstates what it can do. For much the same reason, you won’t find products labeled “waterproof” or “sweat proof.” To get a designation as “water resistant,” a product will have to show effectiveness for 40 minutes in a testing laboratory.Back to top
How should I change the way I select a sunscreen under these new regulations?
Look for the designation of “broad spectrum” to indicate protection from both UVA and UVB radiation, and always choose a sunscreen with an SPF of at least 15 — though I recommend an SPF of 30 or higher for daily use, and an SPF of 50 or higher with an indication of “water resistance” for sports or other outdoor activities.
Whatever product you select, make sure that you like the way that it feels and smells, so that you actually use it.Back to top
What should I do with the sunscreen that I have already purchased?
As long as the sunscreen hasn’t expired, you don’t necessarily have to throw it all away. According to my research and that of others, 75 percent of current sunscreens actually meet the criteria for protection from UVB as well as UVA. To check for UVA protection in the products you have now, look for one or more of these ingredients: avobenzone, titanium, zinc, or ecamsule.Back to top
How much sunscreen should I put on?
Use an adequate amount to attain the level of protection stated on the product. For an average adult, the ideal amount is 2 milligrams of sunscreen per square centimeter of skin. This translates to about three tablespoons (1.4 ounces) to cover the back, torso, face, and arms. When used appropriately by an adult in a swimsuit, a typical 6-ounce sunscreen container will be finished in a little over four uses. Put it on 30 minutes before going outside and reapply every two hours if you are staying outdoors for a lengthy period.Back to top
If I only use a broad-spectrum sunscreen with an SPF value of 15 or higher, will I be protected from sunburn, skin cancer, and early aging?
The answer to this is no. Don’t rely exclusively on sunscreen to protect yourself from UV rays. Your first considerations should be to avoid the sun especially during the peak hours of 10:00 am to 3:00 pm, seek shade, and wear sun-protective clothing. In fact, clothing is superior to sunscreen in several ways: The protection is constant, the product is cheaper in the long run, and it shields you from UVA exposure.Back to top