Our story on the growing use of nano-sized materials in consumer products in the July issue of Consumer Reports clearly got people thinking about these ultra-tiny materials. Since we published the piece, there's been a lot of media attention focused on sunscreens in particular, with manufacturers and other organizations voicing various opinions about the relative safety of different sunscreen ingredients -- some nano-sized and some not.
But sunscreens aren’t the only nano-formulated products that have caused a buzz. There's growing consumer interest in these new materials and concern over their effect on the body and on the environment. And consumers are justifiably questioning what processes and regulations are needed to ensure that nano particles are managed safely throughout the chain of commerce.
To expand the dialogue and learn more about consumer perspectives on nanotechnology, Consumers Union is collaborating with the Project on Emerging Nanotechnologies on a two-day online event, Consumers Talk Nano, on October 23rd and 24th. The aim is to enable consumers to communicate online with expert panelists and with each other about this important topic. Register to participate in the dialogue or visit the project's web site to find more resources.
To learn more about nanomaterials, read the FAQ on nanoparticles in sunscreens that follows.
Q. Do all products containing zinc oxide or titanium dioxide contain nanoparticles?
A. We have only tested and confirmed the presence of nanoparticles in eight sunscreen products formulated with these ingredients and cannot confirm their presence in other products without further testing. Not all zinc oxide or titanium dioxide used in consumer products is likely present as nano-sized particles. For many years these chemicals have been widely used in larger forms in food additives, ointments and other products. However, without labeling, neither consumers, nor regulatory agencies such as the Food and Drug Administration can identify products that do contain nanoparticles.
Q. Does Consumers Union recommend against using sunscreens containing zinc or titanium oxides?
A. We do have concerns about the potential toxicity of zinc oxide and titanium dioxide nanoparticles, however, the available research to date is not sufficient to provide a definitive assessment of risk from these nanoparticles in sunscreens. Consumers need to weigh the uncertain risks against the benefits of these and other product formulations for themselves.
FDA approval of these ingredients did not specifically consider the presence or safety of nano-size particles. The test methods to identify nanoparticles of zinc and titanium oxides in sunscreens were developed especially for Consumer Reports.
Because their risks in this size range have not been fully evaluated, we could not compare risks of different formulations or factor such risks into our ratings. We think the Food and Drug Administration should conduct a full safety assessment and that products containing manufactured nanoparticles should be labeled to enable consumers to make an informed choice.
Q. What about other sunscreen ingredients? Have they been adequately assessed for safety? Are they present as nanoparticles?
A. Some other active ingredients in sunscreen, such as octyl-methoxycinnamate (OMC), a carbon-based ingredient, have also shown some potential toxicity in laboratory animal and cell culture studies, raising concerns about their risks.
It’s not clear whether these other ingredients are present as nanoparticles and if so, how that would affect their toxicity. New laboratory methods would need to be developed to detect carbon-based nanoparticles in sunscreens. Although one manufacturer told us that the carbon-based sunscreen ingredient it uses is not in the nano size range, we have not been able to confirm this assertion.
We call on the FDA to conduct a full risk assessment for all active sunscreen and cosmetic ingredients and to require adequate pre-market safety testing of ingredients in the form that’s used in consumer products.
Q. It seems that all sunscreen ingredients have safety concerns, would I be better off not using any sunscreen?
A. No. We’re not aware of any studies that suggest that any long-term risks from sunscreen ingredients outweigh the known benefits of protecting yourself from ultraviolet radiation, which is a known carcinogen. Proper use of sunscreen is just one of several important steps necessary to avoid sunburn and reduce UV exposure.
Q. I’ve heard skin cancer rates are still rising. Does this mean sunscreens don’t really work?
A. No. While it’s true that rates continue to rise for melanoma, the most serious form of skin cancer which accounts for about 6 percent of all skin cancers, scientists are finding a number of factors that may contribute to the trend. Among them: insufficient use of sunscreen, and continued prolonged exposure to the sun. Though it’s difficult to fully assess what role sunscreen efficacy plays, inappropriate use of less effective products may help contribute to the risk by giving consumers a false sense of security, causing them to rely too heavily on sunscreens alone for protection against the sun’s harmful rays.
Our tests found that most sunscreens provide the level of protection that’s claimed on their labels for UVB. But as we stated in a recent report, the SPF rating on sunscreens does not currently reflect protection against the more damaging UVA spectrum, which varied across brands. Some brands protected against UVA for longer periods of time than others. Top–rated brands provide excellent UVA and UVB protection. In our tests for UVB protection, some brands did better than others at maintaining protection after immersion in water (UVA protection after water immersion was not assessed). It is important to re-apply sunscreen every two hours and after swimming to maintain protection and to make sure you don’t stay out in the sun longer than you should. Covering up and wearing and a wide-brimmed hat are also important.
Q. What about the old-fashioned opaque zinc oxide sunscreens, like the ones that made lifeguards’ noses white? Do they contain nanoparticles and are they effective?
A. At the time we tested, we were unable to find products readily available on the U.S. market that remain opaque when applied to the skin. We don’t know for sure if such products would contain naturally-occurring traces of nanoparticles, or have nanoparticles mixed in, nor do we currently know how well such formulations protect against exposure to UVA and UVB. We will continue this investigation and keep you informed of any new information as it becomes available.
Q. Are ingredients characterized as “micronized” really nano-sized?
A. The term “micronized” has been loosely used for many years, but has not been formally defined by FDA or other agencies. Technically, it refers to the process of grinding materials down into small particles rather than the actual size of those particles. Though the term seems to imply that particles would be in the micrometer range, it’s possible that some ingredients may actually be present in the nano form. Efforts are underway in government agencies and trade associations to develop more consistent terminology and definitions for characterizing particle size in the micro and nano range.
Q. Did some sunscreens perform better than others? Did some contain “broad spectrum” ingredients? If so, what are they? How did you test?
A. Broad spectrum ingredients are those that protect against the full range of harmful ultraviolet light: UVA and UVB. Protection against these types differed substantially for different products, and performance could not be predicted by the presence of a given ingredient. For example, most products containing avobenzone were at least very good at blocking UVA, but one was just good. Likewise, most products containing zinc oxide provided at least very good protection against UVA radiation, but one was only fair.
We conducted several tests, using synthetic skin in the lab as well as volunteer panelists, to measure how well sunscreen products protected skin from ultraviolet radiation. The primary test that formed the basis for our Ratings was done with human panelists and was based on the Japanese Cosmetic Industry Association recommended method for UVA protection.
Products at the top of the ratings in both water resistant and non-water resistant categories provided excellent protection against the type of ultraviolet radiation known as UVA, which can cause skin cancer and wrinkles. Products with water resistance claims were tested for UVB protection after soaking volunteers’ treated skin for durations ranging from 40 minutes to 8 hours, depending on claims. All products rated Excellent maintained the specified SPF after water immersion.
Q. Did the sunscreen protection last over time?
A. Products that performed best maintained protection for about an hour and a half under UVA lamps, after being applied to human subjects. Most water resistant products maintained their claimed SPF (UVB protection) when immersed in water for the time period defined by their water resistance claims, which ranged from 40 minutes to 8 hours. Deterioration over the course of the test was minimal. All products maintained more than 90 percent of their claimed Sun Protection Factor (SPF) after water immersion.
Q. I’m allergic to most organic sunscreens, and have always used products containing zinc or titanium oxides. Should I stop using sunscreens?
A. No. We think the choice of sunscreen is best made between you and your doctor.