Advanced Search

Find your sunscreen
Filter your search

Limit Results

Sort results


Sunscreen: How it Works, What it Means

FAQs: Your Sunscreen Questions. Our Answers. Sunscreens: How it Works, What it Means.

Sunscreens: How it Works, What it Means

Which sunscreens are best and why?

The ideal sunscreen would block most ultraviolet A and B rays with active ingredients that do not break down in the sun, so the product remains effective. It would also contain only active and inactive ingredients proven completely safe for both adults and children. No sunscreen on the U.S. market meets all these criteria, and consumers have no simple way to know how well a particular product stacks up. That’s why EWG created this guide to safer and more effective sunscreens.

Is a good sunscreen all I need to stay safe in the sun?

No. Sunscreen can provide only partial protection against the harmful effects of the sun. Limiting sun exposure and wearing protective clothing are more important ways to protect your skin from cancer and premature aging.

Do not use sunscreen to prolong the time you spend in the sun, and be especially careful about exposure between 10 a.m. and 4 p.m., when the sun’s rays are most intense. And remember that UVA radiation doesn’t decline as much as UVB does when the sun is lower in the sky or when it’s overcast. UVA rays can even penetrate glass.

Apply sunscreen generously 15 minutes before going outside, and reapply it often – at least every two hours. Even the best sunscreen won’t work well if you don’t use it correctly.

Doesn’t the government ensure that sunscreens protect us?

No. After a 34-year process of reviewing sunscreen safety and efficacy, the Food and Drug Administration has not yet finalized rules on sunscreen ingredient safety and product effectiveness.

In February 2019, the FDA released its draft sunscreens final monograph, which, if implemented as is, would improve considerably the safety and effectiveness of products on the U.S. market. The agency’s proposal would strengthen UVA standards for SPF products and cap SPF values at 60+. The proposal allows spray sunscreens to stay on the market, but manufacturers of these products would have to test the spray to ensure they don’t release small particles that could harm the lungs.

The FDA currently allows American sunscreen makers to claim their products are “broad spectrum,” even though many offer much poorer UVA protection than sunscreens sold with that label in other countries. Many of the products in our guide could likely not be sold in Europe because they provide inadequate UVA protection. Manufacturers there voluntarily comply with a European Commission recommendation that all sunscreens provide meaningful UVA protection relative to their SPF. FDA rules do not bar products with sky-high SPFs that prevent sunburn while leaving users at risk of UVA-related skin damage.

Which sunscreens are best for children?

Since kids are more vulnerable to sun damage and the harmful effects of chemical exposure, they should use a sunscreen rated highly for safety and effective protection from UVA and UVB radiation. If your child plans to swim and play in the water, look for a water-resistant sunscreen. Don’t buy sprays or products with bug repellent. Apply sunscreen generously before children go outside, and reapply it often.

Sunscreen is just one part of a sun-healthy lifestyle. Limiting sun exposure and wearing protective clothing are more important. The American Academy of Pediatrics recommends avoiding sunscreen for children younger than six months, but since they don’t yet have protective melanin proteins and need to be kept out of the sun, apply apply a minimal amount to exposed skin (AAP 2008) if you can’t find protective shade and clothing.

How much sunscreen is enough, and how often should I reapply?

Follow the advice of the American Cancer Society and apply sunscreen early, regularly and generously – 15 minutes before going outside and at least every two hours thereafter. Reapply it after being in the water, sweating a lot or towel drying, since these activities can remove sunscreen. (One study indicates that it’s best to reapply sunscreen after the first 15 to 30 minutes in the sun.)

Plus, don’t skimp on sunscreen. Studies have shown that people typically apply only one-fourth to two-thirds of the amount required to achieve the product’s SPF rating. The American Academy of Dermatology recommends applying one ounce – about a palmful – evenly to all exposed skin.

Will sunscreen protect me from cancer and wrinkles?

The principle forms of ultraviolet radiation – UVA and UVB – are known to contribute to skin cancer, wrinkling and skin aging. To get the most protection, use a product that filters out a significant proportion of both types. Many American sunscreens bear labels that boast “broad spectrum” protection, but their UVA protection is often inadequate. The SPF number indicates how effectively a particular sunscreen protects skin from UVB rays and sunburn – the higher the number, the stronger the protection. But SPF values say little about UVA protection.

The FDA’s rules for broad-spectrum sunscreens are too weak. In 2018, EWG estimated that 99 percent of all sunscreens on the market could legally use the “broad spectrum” label even though our estimate is that half could not be sold in Europe due to inadequate UVA protection.

There are critical differences among sunscreens, but the labels don’t provide enough information. This is one of the primary reasons EWG created its sunscreen guide – to give consumers much-needed information about how effectively their sunscreen blocks both types of harmful radiation.

What does SPF mean?

SPF stands for sun protection factor. It measures protection against sunburn, which is mostly caused by UVB rays. If your skin would normally burn after 10 minutes in the summer midday sun, for example, wearing a thick layer of an SPF 15 sunscreen would theoretically allow you to stay in the sun for 150 minutes (10 x 15) without burning. That’s only a rough estimate, and in real world conditions, sunscreens do not provide that level of protection. Skin type, the nature of your activities in the sun (e.g., whether they involve water or sweat) and the intensity of sunlight may affect how much safety it gives you.

In addition, SPF ratings can be confusing or misleading. People rarely apply enough sunscreen to achieve the labeled SPF. The numbers do not reflect UVA protection. The FDA has warned that high-SPF products can create a false sense of security, contain higher concentrations of allergenic or irritating ingredients, and offer little additional sun protection (Branna 2011).

How high an SPF should I use?

Pick the SPF appropriate for your skin type and expected time in the sun. UVA protection in American sunscreens maxes out at about 15 to 20. Higher SPF products will not offer proportionally higher protection. The American Cancer Society recommends that people use a sunscreen with an SPF of at least 15, whereas the American Academy of Dermatology suggests 30. EWG recommends avoiding sunscreens with SPFs higher than 50. It is more important to apply sunscreen properly than to use one with an ultra-high SPF. Most people put on only one-quarter to two-thirds as much as it takes to achieve the product’s SPF rating (Diaz 2012, Grosick 2004).

How do sunscreens work?

The active ingredients in sunscreens absorb, reflect or scatter UV radiation, changing the skin’s response to sunlight. Sunscreens typically contain a combination of chemicals known to protect effectively against certain wavelengths of UV light. Some work better than others, as do some combinations of active ingredients.

For years, manufacturers created sunscreens that were effective at screening out UVB radiation only – the type of rays that cause sunburn and increase the risk of skin cancer. More recently, scientists realized that UVA radiation is also harmful, so sunscreen manufacturers have tried to create sunscreens that protect skin from both UVB and UVA radiation.

Many American sunscreens lack strong UVA protection, due to weak rules about UVA protection and the lack of approved ingredients. However, in 2019, FDA proposed strengthening the UVA standards for SPF products, bringing them more in line with European sunscreens, which provide greater UVA protection in relation to SPF (FDA 2019).

Has using sunscreens lowered skin cancer rates?

Controlled studies comparing sunscreen users and non-users find that sunscreens reduce the risk of squamous cell carcinoma but not basal cell carcinoma. The evidence about melanoma, the most dangerous skin cancer, is mixed. Despite greater sunscreen use and sun awareness, the rates of new melanoma cases among American men, women and children continue to climb. Most experts recommend that people use sunscreen but without relying on it exclusively to prevent sun damage (NCI 2007, van der Pols 2006, Green 1999).

Why shouldn’t I use sunscreen sprays and powders?

EWG does not recommend powder and spray sunscreens, because of concerns about inhalation and inadequate sun protection. The FDA is proposing additional tests on spray sunscreens to verify the absence of small particles that may penetrate and damage the lungs (FDA 2019). EWG is especially concerned about inhalation of nanosize and micronize zinc and titanium in powdered sunscreens and makeup products.

Inhalation is a much more direct route of exposure to these compounds than skin penetration, which appears to be low in cases of healthy skin. If you want the benefits of a mineral sunscreen, choose a zinc- or titanium-based lotion. If you must use a pump or spray sunscreen, lower your inhalation risk by applying it to your hands and then apply it to the face with your hands.

What about products that combine sunscreen with bug repellent?

EWG recommends against using them, and the FDA draft final monograph, released in February 2019, proposed ending the sale of sunscreens with insect repellents. For starters, bugs may not be a problem during the hours that UV exposure peaks. Also, you may need to reapply sunscreen more frequently than bug repellent, or vice versa.

It’s wise to avoid using repellent chemicals on your face. Most worrisome of all, sunscreens often contain penetration enhancers, which help chemicals soak into the skin. Studies indicate that concurrent use of sunscreens and pesticides leads to increased skin absorption of pesticides (Wang 2006, Wang 2007).

I am using a high-quality sunscreen with SPF 50, so why do I still get burned?

In theory, with proper use of an SPF 30 sunscreen, you should be able to endure 30 times more sun exposure before burning than if you were not wearing sunscreen. “Proper use” means applying sunscreen 20 to 30 minutes before being exposed to the sun, applying an ounce or more over your entire body (that’s more than you think!) and reapplying it frequently – every two hours, and after swimming, sweating or toweling off.

amount of lotion. That means an SPF 50 product will work more like SPF 7, and you’re more likely to come home from the beach with a sunburn.

How do you remove sunscreen?

Chemical-based sunscreens break down in the sun and lose their effectiveness over time. Normal swimming, toweling and sweating also remove sunscreen. At the end of the day, warm water and soap are the best way to remove remaining sunscreen.

How should I protect my pet from the sun?

Animals can get sunburned and even get skin cancer, especially where they don’t have fur or hair. Avoiding peak sun intensity – the hours between 10 a.m. and 4 p.m. – is the best strategy. The American Animal Hospital Association cautions that only fragrance-free, pet-specific sun products should be used on animals. Cats’ grooming behaviors make them especially vulnerable to the risk of swallowing harmful ingredients in sunscreens (Rainey 2009).

Should I be concerned about vitamin A in my sunscreen?

EWG recommends that consumers avoid sunscreen that contains vitamin A, also called retinyl palmitate. Data from a study by scientists at the FDA and the National Toxicology Panel (NTP 2012) showed that retinyl palmitate may speed the growth of skin tumors when applied to skin in the presence of sunlight. The German and Norwegian governments have warned that many people are exposed to excessive amounts of vitamin A, and personal care products contribute to this problem.

People who want to limit their exposure to vitamin A should avoid retinyl palmitate, retinoic acid, retinyl lineolate and retinyl acetate in sunscreens, lotions, lip products and other leave-on cosmetics until more information is available about their safety.


Get the App

EWG's Skin Deep® Mobile App

Take EWG's Sunscreen Guide with you! Download the Healthy Living App Today

Take EWG's Sunscreen Guide with you! Download the Healthy Living App Today

Get the App Download App

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

Get the Guide