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Sunscreen Glossary

SPF. Sun protection factor, or SPF, is a measure of the erythema or skin redness protection that sunscreens are designed to provide. The SPF is primarily a measure of protection against UVB rays, not a measure of how long you should stay out in the sun.

SPF also does not take into consideration harmful UVA rays, which may lead to the development of skin cancer and wrinkles. The SPF number on a label derives from testing sunscreen on people in a laboratory setting using a short burst of high intensity light.

UVA and UVB. Both ultraviolet A, or UVA, and ultraviolet B, UVB, rays play a role in the development of skin cancer. In addition, UVA rays penetrate more deeply and play a greater role in skin aging and wrinkles, whereas UVB rays are responsible primarily for sunburns and skin inflammation.

UVA-UVB balance. Every sunscreen on the U.S. market provides greater UVB protection, which can help prevent sunburn, than UVA protection. This lack of balance can lead to an overexposure to UVA radiation, which may increase the risk for long-term skin damage or cancer.

As a result of Food and Drug Administration restrictions on ingredients and concentrations, sunscreens in the U.S. market offer far less protection against UVA than UVB rays, and this is worse for products with high SPF values. UVA and UVB protection balance is important so that consumers can prevent sunburn and reduce the risk for other types of sun damage.

Broad spectrum. “Broad spectrum” is a claim, defined by the EPA, that is used on products intended to provide coverage from both UVA and UVB rays. However, the bar to being able to use that claim in the U.S. is low. Even products that may tout their broad-spectrum coverage may not adequately protect users from UVA rays. For example, a shirt protects equally from UVA and UVB rays.

Water resistant. There are many marketing claims found on cosmetics that have no legal basis or standard definition, including: natural, hypoallergenic and “free of….” However, the term water resistant is regulated by the FDA. It has a set of standards and testing procedures that require testing a sunscreen for SPF only after a tester has spent 40 or 80 minutes in a pool or tub.

Consumers should be aware that no sunscreen is truly waterproof, and sunscreens should be reapplied according to the product’s directions.

Active and inactive ingredients. Sunscreens are classified as over-the-counter drugs. This means that every sunscreen product sold in the U.S. should include a drug facts panel on the label that includes a list of active and inactive ingredients.

The active ingredients are those that do the work of providing protection from UV rays. The inactive ingredients are the rest of the product formulation, those that may help stabilize the product, add scent, moisturize or make the product feel like other cosmetics.

Zinc oxide and titanium dioxide. Zinc oxide and titanium dioxide are the two mineral-based active ingredients allowed for use in U.S. sunscreen products. These ingredients are often referred to as physical blockers that reflect UV light, but the zinc oxide and titanium dioxide used in sunscreen products are similar to non-mineral ingredients in providing UV protection by absorbing UV rays.

Oxybenzone. Oxybenzone is a widely used chemical active ingredient. It is a skin sensitizer and potential hormone disruptor that may be harmful to both children and adults. Despite the known toxicity concerns about oxybenzone and the fact that it has been found in almost all Americans, the ingredient remains in a majority of non-mineral sunscreens.

Retinyl palmitate, or vitamin A. Retinyl palmitate, or vitamin A, is an antioxidant used not only in sunscreens but also commonly found in other skincare and anti-aging products. According to the results of government tests, retinyl palmitate speeds the development of skin tumors and lesions on sun exposed skin and, therefore, should be avoided in daytime products.

Fragrance. The term “fragrance” can include a blend of nearly 4,000 ingredients. Due to a loophole in cosmetic regulations, companies are not required to disclose the ingredients they use in a fragrance blend and may simply include the term “fragrance” on a label.

Some common ingredients in fragrance blends include phthalates, which have been shown to disrupt hormone activity, and botanicals, which may cause skin sensitization or allergic reactions. Consumers should choose products that disclose their fragrance components or choose a fragrance-free option.


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About the ratings

EWG provides information on sunscreen products from the published scientific literature, to supplement incomplete data available from companies and the government. The ratings indicate both efficacy and the relative level of concern posed by exposure to the ingredients in this product - not the product itself - compared to other sunscreens. The ratings reflect potential health hazards but do not account for the level of exposure or individual susceptibility, factors which determine actual health risks, if any. Methodology | Privacy Policy | Terms & Conditions

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