Choosing a safe and effective sunscreen is crucial for preventing skin cancers. Use it and reapply often. Key TakeawaysSome studies suggest long-term exposure to chemical ingredients in some sunscreens can be toxic and more research is ongoing.Experts say sunscreen sold in the U.S. is safe and effective at preventing skin cancers.Compared to Europe, the
Dermatologists and beauty influencers are taking to social media to proclaim sunscreen as the most important step in a daily skincare routine. The number of people who reports using sunscreen daily has also steadily increased in recent years.
Sunscreen can help prevent skin cancer, the most commonly diagnosed cancer in the United States. At the same time, new research raises questions about whether the tongue-twisting ingredients in a variety of sunscreen products could cause damage to other parts of the body.
Here’s what you need to know to choose a safe and effective sunscreen.
One in five people in the United States will develop skin cancer in their lifetime, according to the Skin Cancer Foundation. Each year, more than 7,600 die from melanoma—the most aggressive form of the cancer.
Sunscreens are rated based on their sun protection factor (SPF). This is a measure of how much ultraviolet (UV) light is required to cause sunburn on skin covered with sunscreen, compared to unprotected skin.
UV light is a kind of radiation from the sun that you cannot see with your naked eye. There are two types of UV light—UVA and UVB. UVA exposure is often associated with wrinkles and other markings of aging in the skin, while UVB is primarily responsible for sunburn. Both types can cause long-term skin damage and can lead to cancer.
Many sunscreen makers use the label “broad-spectrum” to indicate their product protects against both UVA and UVB.
SPF indicates how well the sunscreen protects against UVB radiation. But the amount of protection from an SPF isn’t linear: SPF 15 blocks 93% of UVB rays, while SPF 30 blocks 97% and SPF 50 blocks 98%.
For everyday use, SPF 30 can be sufficient to block harmful UV rays, said Ivy Lee, MD, a board-certified dermatologist at Pasadena Premier Dermatology. But for longer periods of time outdoors, opt for a sunscreen with SPF 50 and above.
“The sun emits UV rays daily—rain or shine—and UVA rays can penetrate windows. Daily sunscreen use is essential to minimize your skin cancer risk, premature aging, and optimize skin health,” Lee told Verywell in an email.
Sunscreens protect the skin differently depending on their ingredients. Chemical sunscreens act “as a sponge” to absorb UV radiation, Lee said. They include chemicals like oxybenzone, avobenzone, octinoxate, and homosalate. These chemicals soak into the skin, absorb the UV rays, convert the light into heat, and release it from the body.
These sunscreens need to be applied at least 15 minutes before going outside to be fully effective.
Mineral sunscreens, on the other hand, form a physical barrier that reflects UV rays away from the skin. Mineral sunscreens tend to be heavier and less water-resistant than chemical sunscreens, but they can also be more gentle to sensitive skin.
“For sensitive skin, individuals with eczema or rosacea, or babies, I recommend mineral formulas because they tend to be better tolerated and less irritating,” Lee said.
Some people prefer chemical sunscreens because they don’t leave behind a white cast. But that easy absorption could mean that harmful ingredients are leaching into the bloodstream and causing damage elsewhere.
A 2020 FDA study detected sunscreen chemicals in blood, breastmilk, and urine of the participants. Although the study showed the potential for these chemicals to affect other parts of the body, it didn't indicate that the ingredients are actually unsafe. The FDA and American Academy of Dermatology (AAD) continue to recommend the use of both chemical and mineral sunscreen.
“There is no evidence that these ingredients when applied to the skin are toxic or actually cause harm. The FDA study did not suggest that these ingredients are unsafe,” Lee said.
But some watchdog groups, such as the Environmental Working Group (EWG), say that sunscreen makers and the FDA should be vigilant in testing chemical ingredients for both short- and long-term health effects, such as skin irritation and the potential to cause cancer.
One of the most commonly used sunscreen chemicals is oxybenzone. Studies indicate that excess oxybenzone, including in people who reapply sunscreen, is linked to outcomes like skin irritation, endocrine disruption, and an increased risk of breast cancer.
The amount of oxybenzone-containing sunscreen a person would have to use to experience adverse health effects, however, remains unknown. One study shows it would take at least 33 years of applying oxybenzone on the whole body daily to achieve the same level of toxicity seen in rats who experienced significant reproductive issues.
Henry Lim, MD, chair of the department of dermatology at Henry Ford Hospital, had co-authored that study. He said it's difficult to remove oxybenzone from the sunscreen market largely due to its high efficacy.
“Oxybenzone—as many of the U.S.-approved UV filters—has been in use since the 1970s. And we as physicians and dermatologists have not seen any signal of the patients having significant noticeable side effects from all this usage of sunscreen,” Lim told Verywell.
Other sunscreen chemicals like octinoxate and homosalate have also been found in relatively high concentrations in the bloodstream of sunscreen users. Researchers have linked octinoxate to endocrine disruption and reproductive toxicity. Homosalate could be associated with hormone disruption and may enable certain chemicals—like pesticides, bug spray, and other harmful ingredients in the sunscreen—to better soak into the skin.
To better understand the effect of these chemicals after being absorbed into the blood, the FDA requested more safety data. The research, which is currently underway, is a particularly large undertaking, Lim said. Scientists will have to closely study the health effects of exposure in animal models and consider how chemicals interact.
Last year, Johnson & Johnson recalled five of its Neutrogena and Aveeno spray sunscreens because they were found to contain benzene, a carcinogen that is also found in cigarette smoke and vehicle emissions. Benzene is not intentionally added to sunscreen but is a contaminant of the manufacturing process.
The U.S. has relatively few approved active ingredients for use in sunscreen, which Lim said limits sunscreen makers. There are only 16 UV filter active ingredients in the U.S. approved by the FDA, whereas Europe has 32.
"In Europe, they have significantly more flexibility in using other filters to replace oxybenzone," Lim said. "In the U.S., it's a bit more challenging.”
Mineral sunscreens tend to be a safer alternative to chemical sunscreens. It mainly contains naturally occurring minerals like titanium dioxide or zinc oxide.
Sunscreen makers sometimes reduce these minerals to tiny particles to minimize the look of white cast in mineral sunscreens. These nanoparticles can be 1,000 times smaller than the width of a human hair.
In its 2022 report, the EWG urged more research on whether zinc oxide and titanium dioxide penetrate the skin and how the nanoparticles of those elements could affect the body. Still, the group said existing evidence shows the elements pose few health risks and gave a “favorable rating” to nanoparticle sunscreens.
The FDA categorizes these nanoparticles as “generally recognized as safe and effective (GRASE)."
If a patient has any concerns about the health or environmental effects of chemical sunscreens, Lim said he recommends using a mineral sunscreen.
Slathering on layers of sunscreen throughout the day can become tedious. Taking other measures to minimize sun exposure can keep your skin safe.
Avoid spending lots of time outside between 10 a.m. and 2 p.m., when the sun is strongest. And consider wearing protective clothing, like long-sleeve shirts, pants, and hats. Clothing made of fabric with a tighter weave tends to provide more protection.
“Sunscreen is important, but of course not the only component,” Lim said.
When wearing sunscreen on exposed skin, be mindful that it can wear off throughout the day. Lee said it’s best to reapply every two hours, and more frequently if spending time in the water or near reflective surfaces like snow and sand. If you wear makeup, Lee recommends using sunscreen powder to refresh your SPF throughout the day.
“The most important selection criteria for sunscreen is its ease of use, which depends on how it feels on the skin, how well it blends into your skin tone, and if it is affordable to purchase on a routine basis,” Lee said. “The best sunscreen for you is the one that you will actually use every day.”
It’s important to use a sunscreen that protects against both UVA and UVB light and has at least an SPF of 30. But it’s equally important to apply the right amount and to reapply often. The AAD recommends using one-third to a half a teaspoon of sunscreen for the face and neck. And most adults should use about one ounce—enough to fill a shot glass—for the entire body.