In June 2011, the US Food and Drug Administration (FDA) concluded a years-long review of the scientific evidence about sunscreens and issued new rules for manufacturers. Medscape spoke with Reynold Tan, PhD, Interdisciplinary Scientist in the FDA's Division of Nonprescription Regulation Development, Office of Drug Evaluation IV/Center for Drug Evaluation and Research, about key changes, important messages for healthcare professionals to convey to patients, and best practices for use of sunscreens in specific populations, including children and the elderly.
Medscape: The new rules allow manufacturers to claim "broad-spectrum" protection only for products that protect against both ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The older sun protection factor (SPF) labels will also still be used. Can you discuss the differences between these 2 designations? For providers wishing to convey a simple message to their patients, which of these designations should be sought before purchasing a sunscreen product?
Dr. Tan: To understand the new labels, it is important to recognize that the sun's harmful UV rays are made of both UVB and UVA radiation rays, and you need protection against both. Although sunburn is primarily caused by UVB radiation, skin cancer and premature skin aging are caused by both UVB and UVA radiation. That's why you need protection against both UVB and UVA protection. SPF refers to the amount of protection from sunburn provided by a particular product and is dependent on the individual's skin type. The SPF value only tells you the level of UVB protection that a product provides. A product labeled only with an SPF value may not provide adequate protection against UVA radiation. That's why consumers should look for products labeled with broad spectrum in front of the SPF value. A broad-spectrum product will have to pass the FDA's test to demonstrate that it provides both UVB and UVA radiation protection.
Products should ideally be labeled both "Broad Spectrum" and SPF15 or higher. Think of it as putting insulation in your attic to prevent heat loss. To be effective, that insulation has to cover the attic wall-to-wall without any leaks and it has to be thick enough to not let heat through. The term "broad spectrum" in sunscreens is like wall-to-wall complete coverage with insulation. You don't want any leaks that will let some harmful UV wavelengths through -- that's what broad spectrum means. The SPF value is like the thickness of the insulation. You need a sufficient magnitude of protection to prevent harm from UV radiation, and that magnitude is SPF15 or higher. That's why having both designations -- "Broad Spectrum" and an SPF greater than 15 -- is important.
The simple message we want providers to give to their patients is to look for products labeled "Broad Spectrum SPF15 [or higher]" under the new label requirements. All sunscreen products are effective in helping prevent sunburn but it's these "Broad Spectrum SPF15 [or higher]" products that are specifically shown by data to reduce the risk for cancer and premature skin aging when used in combination with other sun-protection measures.
You'll notice that other products will be labeled with the SPF value only. And some products may be labeled "Broad Spectrum" but will have an SPF value less than 15. These products will not be allowed to make any claims for skin cancer or premature skin aging risk reduction. These products will be allowed a claim on their labels that they prevent sunburn because all sunscreens are effective for helping prevent sunburn. However, claims for cancer and premature skin aging risk reduction will not be allowed; in fact, these products will have to be labeled with a warning that says the product has not been shown to prevent skin cancer or premature skin aging. Again, these less protective products are products that are labeled with an SPF value only or that are labeled as "Broad Spectrum" with an SPF value of less than 15.
Medscape: Can you clarify some of the other terminology changes that will result from these new rules? What about terms like "sunblock," "water resistant," "waterproof," and "sweatproof"? Will these terms still be allowed on products? What should patients be told about use of these products in situations where they will be exposed to water or will be potentially sweating?
Dr. Tan: Manufacturers will be allowed to use the term "water resistant" for products that have been subjected to a specific test that demonstrates that the product retains its effectiveness in preventing sunburn when applied to skin that is subsequently immersed in water. The water-resistance test is conducted by having human subjects apply the product to their skin and then immerse themselves for different periods in a whirlpool or tub of water. The immersion period is either two or four 20-minute periods. If a sunscreen manufacturer performs these tests and then documents that the SPF value is retained after these periods of water immersion, they are allowed to label their product as "water resistant (40 minutes)" or "water resistant (80 minutes)."
Those are the allowed terms. The terms "sunblock," "waterproof," and "sweatproof" are no longer allowed to be used on products. We think all of these terms overstate the performance of sunscreen products. The term "sunblock" may mislead consumers that a product completely blocks the sun's harmful rays, but we know that all sunscreens allow some amount of UV radiation to reach the skin. No sunscreen product has been shown to completely retain its effectiveness when it's applied to the skin and then the skin is immersed in water, which is why the terms "waterproof" and "sweatproof" will no longer be allowed. Even products allowed to be labeled "water resistant 40 (or 80) minutes" will have to have directions saying that they should be reapplied after swimming or sweating. Although the water-resistance testing is a test of SPF retention, the test is an indication that the active ingredient is still present and effective on the skin, which suggests that broad spectrum, or UVA protection, should be retained also.
Medscape: Can you discuss the recommendations for sunscreen use in special populations, including infants, children, and the elderly?
Dr. Tan: There are no special labeling requirements for specific age groups except in the directions. For children under 6 months of age, the label will advise consumers to check with a healthcare provider. Sun protection in infants should emphasize the use of sun protection measures other than sunscreen use, mainly limiting time in the sun particularly at midday, trying to seek shade whenever you can, and wearing protective clothing and hats. All other age groups can benefit from the use of sunscreens as part of a comprehensive sun-protection program. If people have specific concerns based on a health condition, they should ask their clinician for an appropriate sunscreen product to use. The American Academy of Dermatology Website provides more specific information about sunscreens, helpful for consumers and healthcare professionals.
Medscape: Recognizing that sunscreen products can represent a fairly significant expense for families, should families be counseled to dispose of older products?
Dr. Tan: We don't recommend that any sunscreen product be kept indefinitely because different products have different stabilities. Their manufacturers have to test the stabilities of their products and maintain records of their stability testing. Currently there's a proposed exemption from labeling with expiration dates for products proven to be stable for 3 years and that do not have specific dosage limitations. Some sunscreen manufacturers believe this proposed exemption applies to their products. But we think expiration dates provide important information for consumers.
Consumers shouldn't keep any sunscreen product indefinitely because some include ingredients that are shown by data to be less photostable than others, meaning that they degrade from exposure to light. When they degrade they may lose their effectiveness in protection against UV radiation. No sunscreen should be kept indefinitely.
Medscape: The Environmental Working Group (EWG) has warned about certain chemicals used in sunscreens and claims that 20% of sunscreen products can't be trusted. The most worrisome chemicals, according to the group, are oxybenzone, a synthetic estrogen, and retinyl palmitate, which breaks down in sunlight to photomutagenic compounds. The group has urged regulation of these and 3 other sunscreen chemicals. Has there been any thought about including a discussion of these and/or other possibly hazardous sunscreen chemicals in the guidelines?
Dr. Tan: The FDA's response to the EWG's charge that some ingredients are not safe is that the active ingredients in sunscreens have been used for many years and we have no reason currently to believe that these products are not safe or effective when used as directed. We also believe that the risk of not using sunscreens is much greater than any potential risk posed by the sunscreen ingredients.
The 2 ingredients, oxybenzone and retinyl palmitate, have to be discussed separately. We are aware of the studies about oxybenzone that the EWG is citing. The cited animal studies purportedly show that oxybenzone may cause endocrine disruption. These studies, however, involved oral rather than topical administration and administered very high concentrations of oxybenzone to these animals. Therefore, the results of the cited studies are of questionable applicability to topical administration of oxybenzone, which is typically at much lower concentrations in sunscreens. Beyond that, the results for these cited studies have not proven to be reproducible. That's why we don't think there's clear conclusive evidence that oxybenzone is a safety concern.
We are also aware of the study cited by EWG to support a charge that retinyl palmitate is photocarcinogenic. First of all, retinyl palmitate is not an allowed sunscreen active ingredient. It's just added to some sunscreens as an emollient, a skin conditioner, or an antioxidant. It's not allowed to be labeled for providing protection against the sun. The specific study cited by EWG involved application of retinyl palmitate to mice and subsequent exposure to light, which resulted in an increased number of skin cancer tumors. However, the control group of mice that received the same formulation without the retinyl palmitate developed a high number of tumors as well. The study also used mice that are genetically susceptible to developing cancer and used a formulation that was not a sunscreen product and did not include a sunscreen active ingredient. Therefore, it's questionable whether the study results can be reasonably extrapolated to use of sunscreens by humans. That's why we don't consider that study as evidence that retinyl palmitate in sunscreens can contribute to skin cancer.
More information regarding the new and proposed labeling changes, including the types of sunscreen products affected by these changes, can be found on the FDA Website.
The new and proposed sunscreen requirements published in the Federal Register of June 17, 2011 can be found online.