Sunscreen Basics
Sunscreens use active ingredients to absorb, scatter or reflect the sun’s ultraviolet (UV) rays before they can damage the skin. By filtering out harmful UV rays, sunscreens help prevent sunburn, premature skin aging and skin cancer from developing.
UV radiation in sunlight is divided into several ranges depending on the wavelength. UVB radiation covers the wavelength range between 290 and 320 nanometers. UVA radiation is between 320 and 400 nanometers. Overexposure to either can increase the risk of skin cancer. Here’s what else each of these rays do:
– UVA rays (aging rays) can pass through window glass prematurely aging your skin, causing wrinkles and age spots.
– UVB rays (burning rays) are the primary cause of sunburn and are blocked by window glass.
A sunscreen can be labeled “broad spectrum” if it provides UV protection across the UVB and the UVA wavelength ranges. According to the U.S. Food and Drug Administration (FDA), only products labeled with “broad spectrum” and a sun protection factor (SPF) of 15 or higher protect against sunburn, skin cancer and premature aging if used as directed with other sun-protection measures.
Sunscreens come in a wide range of SPF levels. According to the FDA, a product’s SPF value reflects the sunburn protection level, determined by testing against UVB radiation, which primarily causes sunburn. Products are labeled with their SPF value, and higher values (up to 50) provide greater sunburn protection. Most dermatologists recommend an SPF of at least 30. Testing methods used to develop sunscreen shopping guides (e.g., Consumer Reports, the Environmental Working Group) may not be consistent with those used by the FDA and may not be accurate indicators of a sunscreen’s SPF designation.
Sunscreen Usage
Below are the recommended guidelines, as stated by the FDA:
– Apply SPF 30 or higher 15 minutes before going outside to allow the sunscreen enough time to provide maximum benefit.
– Use enough to cover the entire face and sun-exposed areas of the body (avoiding the eyes and mouth). An average-sized adult needs at least one ounce of sunscreen (about the amount it takes to fill a shot glass) to evenly cover the body from head to toe.
– Fair-skinned people are likely to absorb more solar radiation than dark-skinned people under the same conditions. However, all skin tones need sun protection.
– When outdoors, reapply at least every two hours, and more often if swimming or sweating, and immediately after toweling dry.
Sunscreen Ingredients
Since 1978, oxybenzone has been one of the few FDA-approved active ingredients that provides effective broad-spectrum protection from UV radiation and is approved for children as young as six months old. According to the American Academy of Dermatology (AAD), other common active ingredients in U.S. sunscreens include avobenzone, ensulizole, homosalate, octinoxate, octisalate, octocrylene, oxybenzone, titanium dioxide, and zinc oxide.
All FDA-approved sunscreen ingredients help protect the skin by scattering, reflecting or absorbing UV rays. Sunscreen products must be formulated and tested using FDA-designated clinical trials to meet their SPF label claim.
Sunscreen Regulation
Sunscreens are regulated by the U.S. Food and Drug Administration (FDA) as non-prescription, over-the-counter (OTC) drugs through a monograph system, which establishes various requirements for the product to be sold in the U.S. A monograph specifies the types of ingredients, dosage forms, testing methods, labeling requirements and other related details for a product category such as sunscreens. If a manufacturer follows the sunscreen monograph, sunscreen products do not require separate FDA pre-approval before they can be sold in the U.S.
The cosmetics and personal care products industry has long supported OTC monograph reform. As part of the revised regulation of sunscreens, the FDA issued a proposed Administrative Order in September 2021, largely mirroring provisions made in its 2019 Tentative Final Monograph (TFM). These include revisions and updates related to maximum SPF values, active ingredients, broad spectrum requirements and product labeling.
As part of the proposed Administrative Order, the FDA reiterated its request for additional data for some sunscreen filters currently approved in the U.S. to further evaluate their status as generally recognized as safe and effective (GRASE). Sunscreens made with these ingredients are not considered unsafe by the FDA and will remain on the market to be used while more data is collected.
Sunscreen manufacturers remain committed to working with the FDA to further demonstrate the safety of avobenzone, oxybenzone, octocrylene, octisalate, octinoxate, homosalate and ensulizole. These filters are approved globally in Europe and other regions around the world and have been used in formulations in the U.S. for decades.
Sunscreen and Children
The AAD, the American Academy of Pediatrics (AAP) and the FDA all recommend the following when using sunscreen on babies and toddlers.
For children under six months:
– Avoid direct sun exposure. Since babies’ skin is much more sensitive than adults, use sunscreens only when necessary.
– Keep them in the shade and dress them in long-sleeves, pants, wide-brimmed hats and sunglasses to protect their skin.
For children older than six months:
– Apply an SPF 30 or higher sunscreen to children’s exposed skin 15 minutes before going outside; use water-resistant, broad-spectrum sunscreen.
– Keep children in the shade and dress them in sun-protective clothing such as long-sleeved shirts, pants and wide-brimmed hats, even when wearing sunscreen.
– Reapply sunscreen every two hours or after swimming, playing sports or toweling dry. If a child can apply sunscreen themselves, remind them to cover easy-to-miss spots like ears, neck, feet and hands.
The best sunscreen is the one you’ll use. Both inorganic and organic broad-spectrum sunscreens are safe and designed to stay on the skin. According to the AAD and the AAP, active ingredients such as titanium dioxide and zinc oxide may be less irritating to a baby’s sensitive skin.
Some U.S. states ban students from using sunscreen at school because it is classified as an OTC product. The Personal Care Products Council (PCPC) works with the AAD and the American Society for Dermatologic Surgery Association (ASDSA) on the SUNucateinitiative to promote sun protection and remove barriers to accessing sunscreen and sun-protective clothing. According to the ASDSA, as of May 2023, 27 states have enacted SUNucate-related legislation, and more states are considering similar actions.
Sunscreen and the Environment
There are well-recognized causes of coral reef decline in Hawai’i and the rest of the world, including climate change, land-based pollution and other human activities, such as physical damage to corals from recreational activities. Government agencies and environmental organizations like the National Oceanic and Atmospheric Administration (NOAA), the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the U.S. Coral Reef Task Force have identified rising sea temperatures from global warming as the primary causes of coral bleaching. Addressing the major, proven causes of coral reef decline is key to protecting reef ecosystems. To date, there is no scientific consensus that sunscreen ingredients contribute to coral reef decline.
Concerns about sunscreens’ potential impact on coral have led several scientists to investigate their potential effects, such as bleaching. A recent study evaluated whether these coral studies were relevant and reliable for ecological risk assessment (ERA) and policymaking. It was concluded that serious problems with the test designs undermined the studies, and none were found to be suitable for ERA and/or informing policy. The findings of the studies have also not been reproduced by other researchers – a key process when establishing scientific consensus. International test guidelines have been refined and evaluated extensively to study the effects of chemicals on the environment, focusing on species that provide reproducible responses under specific laboratory conditions. There is no guideline for coral, leading to the large variability in test conditions. Some basic principles relevant to any test weren’t followed:
– Some studies collected coral from the wild without giving adequate time to acclimate to laboratory conditions, which can cause the coral significant stress, confounds the results and isn’t environmentally realistic.
– Test conditions were either not suitable for coral or water quality wasn’t adequately maintained throughout the experiment, which causes stress and can interfere with the results observed.
– UV filterUV filters are ingredients that filter certain UV rays that are found in sunlight and, to a lesser degree, artificial light. UV filter is a general term that is used for sunscreen agents, ingredients used to protect the skin from UV rays, and ultraviolet light absorbers, ingredients use to protect products, packaging and hair from UV rays. levels were often not confirmed in the tests, making it impossible to determine what the coral were exposed to.
– All studies were either inadequately controlled or inadequately replicated. Without proper controls, it is impossible to determine whether an effect was caused by UV filter exposure or unsuitable test conditions. Low replication can lead to false positive or false negative results.
– Many studies only included one or two UV filter treatment levels, preventing an accurate definition of the relationship between UV filter exposure and the level that causes an effect.
– Due to concerns about sunscreens’ potential toxicity to freshwater and marine life, in particular corals, U.S. Congress directed the National Academies of Sciences, Engineering, and Medicine (NASEM) to review the state of the science on their presence and effects in the environment. Sponsored by the U.S. Environmental Protection Agency (EPA), the report examined the potential impact on aquatic life when UV filters are present in water systems, the efficacy of sunscreens in preventing UV skin damage and potential health impacts of reduced sunscreen use. The report summarized a multidisciplinary expert panel’s review of existing science.
The NASEM report found there is currently insufficient relevant and reliable data for key marine organisms (such as coral) to conduct an ERA that adequately considers them. The study acknowledged the public health benefits of sunscreens and provided valuable insights into the current state of scientific knowledge on sunscreens, specifically UV filters. Notably, the report presented three broad recommendations to address existing information gaps:
– The EPA should conduct an ERA for all currently marketed UV filters and any new ones that become available.
– Government agencies, sunscreen formulators and UV filter manufacturers should work together to conduct and disseminate comprehensive research on multiple aspects of UV filters and their impact on the aquatic environment.
– Epidemiological risk modeling and behavioral studies on sunscreen use should be conducted to understand better human health outcomes from changing availability and use.
Policy decisions impacting the public’s health should be based on all necessary scientific data. The NASEM report highlighted data gaps and recommended that EPA conduct ERAs on available UV filters. Until the identified data gaps are filled and the recommended ERAs are completed, making policy decisions on potential bans would be premature. NASEM acknowledged that changes in consumer sunscreen use due to bans could lead to significant adverse public health impacts of increased UV-induced skin cancers.