There’s good reason to question what’s in a sunscreen and the possible health risks of its ingredients.
Companies that make and sell sunscreen ingredients and products should test them thoroughly for potential short- and long-term health effects. This includes tests for irritation and skin allergies. They should also test for skin absorption of ingredients and whether the ingredients could be linked to health effects like cancer, disrupt the hormone system or harm reproduction and development.
The Food and Drug Administration, which oversees sunscreen safety, said in 2021 that out of 16 ingredients it reviewed, only two – zinc oxide and titanium dioxide – are “generally recognized as safe and effective,” or GRASE, based on the available information.
Citing data showing safety issues, the FDA proposed that two rarely used sunscreen ingredients, aminobenzoic acid and trolamine salicylate, are definitively not GRASE.
The FDA proposed that 12 other ingredients are not GRASE, but that’s due to insufficient data rather than an affirmative finding that they are not safe or effective: Avobenzone, cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, oxybenzone, padimate O and sulisobenzone. The agency has requested additional safety data on these ingredients, but they are still allowed for use in products sold in the U.S.
FDA studies show that with even a single application six of these ingredients, oxybenzone, homosalate, octisalate, octocrylene, avobenzone and octinoxate, can be absorbed through the skin at levels above 0.5 nanograms per milliliter, the maximum concentration the FDA says may be found in blood without potential safety concerns.
Evidence of the endocrine-disrupting effects of two of the ingredients, oxybenzone and octinoxate, is mounting. Studies have also highlighted concerns about endocrine-disrupting effects of other ingredients, such as homosalate, avobenzone, octisalate and octocrylene, although evidence is more limited.
In 2021 the European Commission Scientific Committee on Consumer Safety, or SCCS, published final opinions on the safety of three non-mineral ultraviolet, or UV, filters, oxybenzone, homosalate and octocrylene. It concluded that homosalate and oxybenzone aren’t safe in the amounts they’re used. This led the European Union to lower the amount of these filters allowed in certain sunscreens.
The U.S. has different standards, as sunscreen manufacturers are legally allowed to use homosalate and oxybenzone at concentrations higher than the European limits.
The ingredients oxybenzone, octinoxate, octisalate, octocrylene, homosalate and avobenzone are all systemically absorbed into the body after typical sunscreen use, according to studies published by the FDA. These studies also reported that the ingredients could be detected on the skin and in the blood weeks after they were last used.
Other studies have reported detecting sunscreen ingredients in breast milk, urine and blood plasma samples, confirming they’re absorbed into the body through skin.
It’s also possible for sunscreen users to inhale ingredients in sunscreen sprays and ingest some of the ingredients they apply to their lips.
Except for those formulated with zinc oxide, sunscreen products typically include a combination of active ingredients that provide UV protection. Table 1 below outlines human exposure and hazard information for eight common FDA-approved sunscreen chemicals. Additional details and references on health concerns can be found in the following specific ingredient concerns section.
Table 1. Summary of health concerns associated with sunscreen active ingredients.
| Chemical | FDA 2019 proposed classification as safe and effective | Absorbed through the skin | Hormone disruption* | Skin allergy or other concerns* |
| Oxybenzone | No | Yesa | Strong | Some |
| Octinoxate (Octyl methoxycinnamate) | No | Yesa | Strong | Some |
| Homosalate | No | Yesa | Some | Some |
| Octisalate | No | Yesa | No/weak | No/weak |
| Octocrylene | No | Yesa | No/weak | Some |
| Avobenzone | No | Yesa | Some | Some |
| Titanium dioxide | Yes | No/weak | No/weak | Inhalation concerns |
| Zinc oxide | Yes | No/weak | No/weak | Inhalation concerns |
* Strong, some, or no/weak denote the level of evidence available
a Skin absorption evaluation based on findings from Matta et al. (2020), “Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial.” JAMA.
Oxybenzone, or benzophenone-3
The most worrisome sunscreen active ingredient is oxybenzone, according to publicly available scientific research. It is readily absorbed through the skin. The Centers for Disease Control and Prevention found levels of oxybenzone in people was associated with how much sunscreen they used. It causes allergic skin reactions, behaves like a hormone disruptor and may be more harmful to children, since they are more susceptible to the chemicals’ effects.
A 2017 systematic review of 23 studies found evidence of a link between oxybenzone exposure and reproductive harms.
A 2023 review of 254 studies found mounting evidence that oxybenzone has endocrine-disrupting properties at doses typical of sunscreen use and that people in North America are more highly exposed than those living in European and Asian countries. The review said potential reproductive problems are of the greatest concern from exposure.
The FDA says it needs further data to determine whether oxybenzone can be considered safe and effective.
In a 2019 notice, it said “[The] available literature . . . indicat[es] that oxybenzone is absorbed through the skin to a greater extent than previously understood and can lead to significant systemic exposure. . . . The significant systemic availability of oxybenzone . . . is a concern, among other reasons, because of questions raised in the published literature regarding the potential for endocrine activity.”
The National Toxicology Program found that exposing female rats to high levels of oxybenzone led to increased thyroid tumors and uterus enlargement. Multiple studies published after this and the FDA reports show oxybenzone can alter the structure of the mammary gland and surrounding cells in mice, in ways that may be related to the process through which normal cells transform into cancer cells, leading to the development of tumors.
Investigators at the University of California, Berkeley, reported a dramatic drop in teen girls’ exposure to oxybenzone in cosmetics when they switched from their usual products to replacements without it. This suggests sunscreens are a significant source of exposure.
The European Commission in 2021 reported current human exposure levels to oxybenzone were unsafe. It proposed restricting the ingredient to just 2.2 percent in body lotion and spray sunscreen. That’s 60 percent lower than the 6 percent allowed in U.S. sunscreens.
Several countries, and Hawaii, have banned the sale of sunscreens containing oxybenzone because it may harm marine life.
Octinoxate, or octyl methoxycinnamate
Octinoxate is a non-mineral UV filter that can cause allergic reactions. It is readily absorbed into the skin and continues to be absorbed after sunscreen is applied. A 2020 FDA study found it in blood samples at levels 16 times above the agency’s proposed safety threshold.
In 2024, the European Commission found it could not determine the safety of current octinoxate use levels due to concerns about endocrine disruption and genotoxicity. The commission is finalizing this opinion.
The opinion reviewed several studies on octinoxate exposure in cells and rats indicating octinoxate can interfere with the endocrine system. There’s some evidence the octinoxate can block normal androgen and progesterone signaling, leading to reduced levels of testosterone and progesterone in rats. A study of Chinese elementary and high school children found exposure to octinoxate in boys, measured by urinary concentrations, was linked to delayed onset of puberty. Another animal study reported octinoxate affects the metabolic system.
As with oxybenzone, several countries and Hawaii ban the sale of sunscreens with octinoxate, and for the same reason.
Homosalate
Homosalate is a non-mineral UV filter widely used in U.S. sunscreens. Homosalate can penetrate the skin and may disrupt hormones. The FDA says a lack of data prevents it from determining whether it is safe and effective for use in sunscreens.
The European Commission recently said that, citing concerns about potential hormone disruption, homosalate has a recommended maximum concentration of 0.5 percent in sunscreen products. A concentration limit this low would effectively ban its use in sunscreens. The SCCS later determined homoslate could be used at a concentration of 7.34 percent, but only in products for the face.
The FDA allows U.S. sunscreen manufacturers to use homosalate in concentrations up to 15 percent in all product types.
Octisalate, or ethylhexyl
Octisalate, a non-mineral UV filter, readily absorbs through the skin at levels 10 times the FDA’s cutoff for systemic exposure. The FDA requires additional safety tests for ingredients that might be absorbed above this level. In 2019, the agency said more research must be conducted if it is to determine whether octisalate can be classified as safe and effective to use in sunscreens.
A case report showed the chemical has been linked to allergic contact dermatitis. Data from the Environmental Protection Agency suggests it may weakly interact with the estrogen receptor, although another study found no effect.
Octocrylene
Octocrylene readily absorbs through the skin at levels about 14 times the FDA’s cutoff for systemic exposure. But the agency says there’s not enough data to determine whether the chemical should be classified as GRASE.
Octocrylene is often contaminated with benzophenone, a carcinogen. According to one study, benzophenones levels can increase in products when octocrylene breaks down to become benzophenone. The European Commission said there is some evidence, although inconclusive, of octocrylene’s hormone-disrupting potential. Current use concentrations up to 10 percent are considered safe.
Octocrylene has been linked to marine toxicity, with the potential to harm coral health.
Avobenzone
Avobenzone is a widely used non-mineral filter that provides protection from ultraviolet A, or UVA, rays and is often used with other non-mineral active ingredients in products offering broad spectrum protection. Avobenzone was detected on average at levels nine times the FDA’s cutoff for systemic exposure.
Because avobenzone is not stable, it must be paired with other ingredients that act as stabilizers to prevent it from breaking down in the sun. Breakdown products of avobenzone have been shown to cause allergic reactions.
Avobenzone can also disrupt the endocrine system. Cellular studies have shown that, at low doses, it blocks the effects of testosterone. Exposure to a mixture of homosalate and avobenzone reduced the levels of testosterone in male zebrafish.
Titanium dioxide and zinc oxide
Mineral sunscreens are made with titanium dioxide and zinc oxide, usually in the form of nanoparticles. The FDA in 2021 proposed that both titanium dioxide and zinc oxide be classified as GRASE. Evidence suggests that few, if any, zinc or titanium particles penetrate the skin to reach living tissues.
The International Agency for Research on Cancer classifies titanium dioxide as possibly causing cancer in humans due to potential exposure through inhalation. For this reason, powdered and spray formulations containing titanium dioxide are a concern for health. Zinc oxide may also be inhaled when used in spray and powder products
In general, mineral sunscreens tend to rate better than chemical sunscreens in EWG’s sunscreen guide. But to improve the chemicals’ stability when exposed to sunlight and prevent them from breaking down, manufacturers use forms of minerals coated with other inert chemicals.
EWG supports stronger guidelines and restrictions on the types of zinc and titanium used in sunscreens, including nanoparticles.
Other active ingredients
The FDA in 2006 approved mexoryl SX, an uncommon active ingredient in the U.S., for use in one specific sunscreen formulation. This ingredient offers strong UVA protection, and public research provides no evidence of hormone disruption and few instances of skin allergy. But the FDA’s analysis showed there wasn’t enough data to classify the ingredient as safe and effective.
Aminobenzoic acid, also known as PABA, and trolamine salicylate are active ingredients that are no longer commonly used in U.S. sunscreens. The FDA’s 2019 proposal concluded that the risks of these chemicals outweigh their benefits and proposed classifying them as unsafe, not GRASE.
Sunscreen boosters
Many companies use inactive ingredients in their formulations to increase the sun protection factor, or SPF, values of their products. This may include antioxidants that reduce skin redness or ingredients that absorb UV light, like butyloctyl salicylate, or BOS.
BOS can be seen high on the ingredient list of many mineral sunscreen products, indicating potentially high use concentrations, comparable to levels of other structurally similar UV-filters like homosalate and octisalate.
Safety concerns about BOS and other salicylates such as homosalate and octisalate stem from their potential absorption and metabolism in the body to salicylic acid.
An EU assessment suggests classifying this broad group of similar chemicals as potential reproductive and developmental toxicants. Because of the EU assessment and animal studies showing harm to reproduction and the developing fetus, salicylic acid and several other salicylates cannot be used in kids’ products in the EU.
There may be differing degrees of skin absorption and rates of conversion to salicylic acid for individual compounds. While EWG continues to research the safety of these ingredients, we do not include products with butyloctyl salicylate on the best baby and kids lists.
Other inactive ingredients
EWG also continues to urge the FDA to look closely at the so-called inactive ingredients in sunscreens, which typically make up half to 70 percent of these products. Like cosmetic ingredients, these inactive sunscreen ingredients are unregulated.
EWG recommends the FDA thoroughly investigate the safety of all sunscreen ingredients to ensure none causes damage to the skin or leads to human health harms.
