Sunscreens with a high sun protection factor value, or SPF, are popular because consumers often believe these offer the best protection from the sun’s harmful rays. That’s not always true.
SPF values are an unreliable measure of a sunscreen’s effectiveness. A good sunscreen should provide equal broad-spectrum protection, against both ultraviolet, or UV, A and B rays. But the SPF value primarily reflects how well a product will protect from UVB rays, the main cause of sunburn and some skin cancers, such as squamous cell carcinoma.
Sun protection products originally aimed to reduce sunburn. Today, it’s known that some UV rays, such as UVA, don’t cause sunburn but can lead to health harms. UVA rays, which penetrate the skin more deeply than UVB rays, are associated with skin aging and cancer, such as melanoma.
SPF values are also unreliable because the test method companies must use to determine a product’s value is imprecise. It requires someone to determine a change in the skin redness of a small handful of human participants exposed to UV light in a lab. These results may differ based on the evaluator, testing instrumentation or participant skin type. And SPF test conditions used for labeling significantly overestimate the protection a sunscreen may provide outdoors.
During the last two decades, EWG has tested U.S. sunscreen products, and reviewed the results of other studies, to verify the sun protection performance. The findings don’t create a lot of confidence in relying solely on SPF values to measure protection accurately.
Independent tests have also revealed shortcomings with the Food and Drug Administration’s current requirements for UVA protection from sunscreens.
An EWG peer-reviewed study published in Photodermatology, Photoimmunology and Photomedicine found a number of sunscreens sold in the U.S. provide inadequate UVA protection, compared to the listed SPF’s claim. This gives sunscreen users a false sense of protection, which can lead them to use less sunscreen than they need and risk overexposure.
EWG tested 51 sunscreen products in a laboratory for UV absorption using in vitro methodologies. On average, products reduced UVA exposure by only half of what would be expected based on the labeled SPF. Just 18 of 51 products passed the UVA protection test required of sunscreens sold in Europe.
Given EWG’s findings, consumers should assume many sunscreen products on the market offer significantly reduced UVA protection compared to UVB protection. We found the UVA protection factor achieved was, on average, only a quarter of products’ labeled SPF.
Most sunscreens tested by EWG also failed to show reliable UVB protection. Our research found that most sunscreens provided just 42 to 59 percent of the UVB protection that might reasonably be expected from what’s stated on the SPF label.
Many products tested would not meet the UVA standards set by the European Commission for products sold within the European Union. The EC recommends sunscreen products’ ratio of UVA protection to SPF be at least one-third. But only about a third of the products tested passed the EU standard, whereas more than nine out of 10 – 94 percent – would get the FDA’s green light.
The FDA published test results in 2019 finding significant differences in UVA protection among products with the same SPF. Despite the FDA’s awareness of large differences in UVA protection and the connection between UVA exposure and skin cancer, the agency has yet to strengthen the required UVA protection of SPF products.
The FDA proposed new rules in 2021 that would require a slightly increased minimum level of UVA protection. But the proposed rules haven’t taken effect nor do they go far enough to ensure adequate UVA protection.
Don’t place too much trust in high SPF (50+) products. They have at least four flaws:
1. Poor UV balance
A sunscreen’s SPF rating has little to do with its capacity to shield skin from UVA rays. As SPF increases, the ratio of UVA protection decreases in U.S. sunscreens. FDA researchers concluded in 2019 that high SPF products with poor UVA protection could increase the risk of skin cancer and early skin aging.
High SPF products suppress sunburn much more effectively than protect from UVA-induced damage, such as suppression of the immune system, formation of harmful free radicals in skin, and development of melanoma.
2. Consumers misuse high SPF products
High SPF products tend to lull users into a false sense of security, so they stay in the sun longer and overexpose themselves to both UVA and UVB rays well past the point when users of low SPF products would likely head indoors. So they get as many UVB-inflicted sunburns as unprotected sunbathers and likely absorb more damaging UVA radiation.
Philippe Autier, a scientist formerly at the World Health Organization’s International Agency for Research on Cancer, was one of the first to conduct studies of sunbathers. Autier believes that high SPF products spur “profound changes in sun behavior” that may account for the increased melanoma risk found in some studies. He published studies in 1999 and 2000 confirming that European vacationers spent more time in the sun with an SPF 30 product instead of SPF 10
Misinterpretations of the meaning of SPF have also been reported more recently, including in a 2018 study that reported dermatology patients answered questions about SPF and water-resistance of sunscreens correctly only about 30 percent of the time.
The FDA cited Autier’s 2007 review paper on the associations between SPF and sunscreen use behavior in the agency’s 2021 proposed new regulations for sunscreen.
3. Sunburn protection is only marginally better with high SPF
Sunbathers often assume they get twice as much protection from SPF 100 sunscreen as from SPF 50. But the extra protection is negligible.
Properly applied SPF 50 sunscreen blocks 98 percent of UVB rays; SPF 100 blocks 99 percent. When used correctly, sunscreen with SPF values between 30 and 50 offers adequate sunburn protection, even for people most sensitive to sunburn.
4. High SPF products may pose greater health risks
High SPF products require greater concentrations of sun-filtering chemicals than low SPF sunscreens. Some of these ingredients may pose health risks when they penetrate the skin and have been linked to tissue damage and potential hormone disruption. Some may trigger allergic skin reactions.
If studies showed that high SPF products were better at reducing skin damage and skin cancer risk, the extra chemical exposure might be justified. But they don’t. So it’s prudent to choose sunscreens with lower concentrations of active ingredients, for example SPF 30 instead of SPF 70.
The FDA has long contended that SPF higher than 50 is “inherently misleading.” SPF values are limited to 50+ in most countries. In 2011, the FDA proposed prohibiting labels higher than SPF 50+.
But in its 2021 final draft sunscreen order, the agency proposed raising the cap to 60+. EWG believes the FDA should reconsider this change and instead cap values at 50+.
