Long days at the beach, flip-flops and tank tops, backyard barbecues — so many of our favorite things about summer are designed to let us soak up the sun. And time spent in the sun can be good for us, for some fundamental reasons.

For example, the sun regulates our circadian rhythms, which are critical to a good night’s sleep, according to the National Institute of General Medical Sciences. The sun also provides our bodies with a crucial source of vitamin D and can help to cheer us up when we’re feeling down, notes past research. Meanwhile, other past research links increased vitamin D intake with a lower risk of developing certain cancers, including breast, prostate, and colorectal cancer.

But that’s no excuse to let your guard down when it comes to sun protection. The sun causes the vast majority of melanoma and nonmelanoma skin cancers (86 percent and 90 percent, respectively), according to the Skin Cancer Foundation. And skin cancer is the most commonly diagnosed cancer in the United States, with 1 in 5 Americans expected to develop skin cancer by age 70. The sun is also responsible for an estimated 90 percent of visible skin aging.

That’s why for decades now, shopping for sunscreen has been a fact of life — and as more research focuses on the pros and cons of different sunscreen ingredients and labeling rules, it’s also become increasingly confusing. As critically important as it is to reduce the risk of skin cancer, many people remain in the dark about some basic facts. A study published in JAMA Dermatology found that fewer than half of 114 patients surveyed at a dermatology clinic knew the meaning of common sunscreen terms like “broad spectrum” and “SPF.”

“Labels are confusing,” says the board-certified dermatologist Joshua Zeichner, MD, the director of cosmetic and clinical research at Mount Sinai Hospital's Department of Dermatology in New York City. “There are so many different types of ingredients, formulations, and levels of possible protection. In a competitive environment like sunscreen, there are so many different products on the market making many different claims. Ultimately, language on the bottles may lead to consumer confusion.”

What follows is an essential guide to understanding the most common terms found on sunscreen labels, to help you find the product that’s best for you and your family.

Active, Inactive

Because sunscreens are classified as over-the-counter drugs in the United States, the U.S. Food and Drug Administration (FDA) requires the label to include a drug facts panel that lists active ingredients and inactive ingredients.

“The active ingredients are the ingredients that do the work of protecting you from UV rays. The inactive ingredients are the rest of the product formulation that may help stabilize the product or provide additional functions,” says Carla Burns, a research and database analyst at the Environmental Working Group (EWG) in Washington, DC, who managed the EWG 2022 Guide to Sunscreen.

Antioxidants

“Antioxidants are compounds that absorb energy from free radicals and prevent them from causing damage to the skin,” says Dr. Zeichner. “Think of them as fire extinguishers that put out skin inflammation.” Common antioxidants include vitamin A, vitamin C, vitamin E, beta carotene, and selenium, according to FamilyDoctor.org.

Avobenzone

According to the U.S. National Library of Medicine, Avobenzone is a topical, broad-range UV protector that blocks UVA 1, UVA 2, and UVB wavelengths, limiting the impact of UV rays on skin. While avobenzone is a common ingredient, don’t let its ubiquity lull you into a false sense of security: There is considerable ongoing controversy as to its safety, and avobenzone is 1 of 12 sunscreen ingredients on which the FDA is currently conducting further research.

Baby

While this word shows up in many cheesy pop songs, when you see it on a sunscreen label, it means something completely different. According to the American Association of Dermatology, the FDA has no strict definition for this term. But when you see “baby” on sunscreen packaging, it typically (though not always) means that it’s a mineral or physical sunscreen.

“Sunscreens that are recommended for babies tend to be not as readily absorbed and reflect light instead of converting the light to heat, which is more difficult on sensitive skin types including that of babies,” explains New York City dermatologist Michelle Henry, MD. And PS: These formulas work just as well for grown-ups who want to avoid chemical sunscreens.

Broad Spectrum

“This is one of the most important terms to look for when reading a sunscreen label,” says Dr. Henry. “Broad spectrum means that it protects you from both UVA and UVB [rays], which are both important not only for skin cancer prevention but also to reduce accelerated aging.” UVA rays contribute to accelerating signs of aging, whereas UVB rays contribute to sunburns, notes the University of Iowa.

Clinically Proven

This may sound impressive — but actually, there’s no strict regulation around this term. According to the American Academy of Dermatology (AAD), “clinically proven” just means that the product was given to consumers to try — not that it has undergone clinical trials or been approved by the FDA.

Chemical

“Chemical sunscreens contain compounds that absorb UV light and prevent it from penetrating into the skin,” says Zeichner. “They absorb fully into the skin, but may cause irritation in people with sensitive skin.” They’re found in most broad spectrum sunscreens, but according to the Environmental Protection Agency, these chemicals, such as UVA-absorbing oxybenzone or a benzophenone, can in rare cases cause skin reactions, including acne, burning, blisters, dryness, itching, rash, redness, stinging, swelling, and tightening of the skin.

Cruelty-Free

If a product is labeled is cruelty-free, that means that not only was the final product itself not tested on animals, but the raw materials used to make the formula were also not tested on animals, according to the FDA. With that being said, there’s currently no regulation in the United States or Canada when it comes to the label “cruelty-free” or “not tested on animals.” If you want to ensure that your sunscreen has not been tested on animals at any stage of the development process, look for products whose labels contain the Leaping Bunny certification. (This certification is offered by the Coalition for Consumer Information on Cosmetics, a band of eight international animal protection groups.)

Dermatologically Tested

This term indicates that a dermatologist has been in charge of product tolerance tests, carried out with voluntary test subjects, according to the skin-care line website Dermaviduals.

Fragrance

“The term 'fragrance' can include a blend of nearly 4,000 ingredients in sunscreens,” says Burns. “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,” says Burns. “Some common ingredients used in fragrance blends include phthalates, which have been shown to disrupt hormone activity, and botanicals, which may cause skin sensitization or allergic reactions.” Burns says your safest bet is to opt for sunscreens that list exactly what their fragrance components are, or better yet go with a fragrance-free choice.

Free Radicals

Free radicals are not hippies who escaped from prison. Free radicals are molecules that have high levels of energy, says Zeichner. “In the skin, they can damage cells’ DNA and weaken collagen, can advance skin aging and cause skin cancer.” According to an analysis carried out by the EWG and published in Photodermatology, Photoimmunology, & Photomedicine in October 2021, many sunscreens don’t provide adequate protection from UVA rays, which penetrate skin tissue more deeply and are most responsible for generating free radicals. According to past research, too many free radicals in the body can lead to oxidative stress, which is linked to various chronic illnesses, including cancer and autoimmune disorders.

Hypoallergenic

According to Dermaviduals, this term suggests that a sunscreen is less likely to cause allergic reactions, which would be a good thing, especially for people with sensitive skin. But the FDA has no definition of the term “hypoallergenic,” so companies can label products with that term without having to prove they meet any hypoallergenic standards. “Usually the term means that the product is free of fragrances and dyes,” says Dr. Zeichner. “Whether a product is hypoallergenic or not typically did not impact the sun protection benefits.”

Insect Repellent

While some products offer both protection from the sun and bothersome insects, according to the Mayo Clinic, it’s better to use separate sunscreen and insect repellents. “Application of sunscreen and insect repellent at the same time can lead to an increase in penetration of insect poison through the skin,” says Zeichner. “Applications should be separated out in time by 20 minutes.”

Mattifying

If you want to protect yourself from the sun’s harmful rays without looking too shiny, or you have oily skin, search for a mattifying sunscreen. This type of sunscreen is formulated with oil-absorbing ingredients, notes Henry. Keep an eye out for clays (like kaolin, bentonite, or montmorillonite), charcoal, talc, aluminum starch octentylsuccinate, rice starch, cornstarch, silica, and nylon-12; these are all oil-absorbent ingredients you may find in your skin-care products, according to skin-care company Paula’s Choice.

Mineral

Mineral sunscreens are also known as physical sunscreens because they act like a shield, sitting on the surface of your skin and deflecting the sun’s rays, explains Zeichner. According to the AAD, mineral sunscreens often contain active ingredients titanium dioxide, zinc oxide, or both. If you have sensitive skin, opt for this type of sunscreen.

Noncomedogenic

According to Henry, noncomedogenic means a sunscreen has ingredients that are less likely to cause breakouts by clogging your skin pores. “Noncomedogenic sunscreens are a good choice for someone who is prone to acne,” she says. “Look for ingredients like zinc and titanium dioxide.”

Oil-Free

“A product that says it is oil free should be free of any oils,” says Henry. “However, that does not mean it is free of other occlusive ingredients that might clog pores. So who should use an oil-free sunscreen? Anyone with acne-prone skin. There’s a difference between oil-free and noncomedogenic. There are products that have some oil but can still be listed as noncomedogenic.”

Organic

No, this doesn’t mean your sunscreen was made with blueberry juice on a small farm in Vermont. According to the Australian Academy of Science, organic sunscreens use organic chemicals (which primarily contain carbon) to filter or absorb UV radiation. Benzophenone, benzotriazoles, cinnamates, and salicylates are some common organic chemics you might see on your sunscreen label. (On the other hand, inorganic sunscreens contain inorganic metal oxides that physically block UV radiation from the skin.)

Oxybenzone

This is perhaps the most controversial of all sunscreen ingredients. Oxybenzone is one of the most common chemical filters found in commercial chemical sunscreens. According to the EWG, the FDA has raised concerns about absorption of oxybenzone into the skin. “Oxybenzone has been reported to be a hormone disruptor; however, based on my currently available data, there’s no proof that this is actually true of Oxybenzone-containing sunscreens,” says Zeichner.

Octinoxate

Here’s a moral quandary: Sometimes what’s good for your skin isn’t good for things with fins. Octinoxate, which PubChem notes is a common sunscreen ingredient, is one example. “Octinoxate is an effective clear UVB sunscreen filter and one of the few sunscreen active ingredients allowed for use by the FDA,” says Supergoop! founder and CEO Holly Thaggard, who is based in Houston. “However, a recent body of research has suggested that octinoxate can potentially be detrimental to coral reefs.” The chemical, along with oxybenzone, contributes to coral bleaching and the destruction of coral larvae, according to the International Coral Reef Institute, which recommends consumers seek reef-friendly sunscreen options. (Save the Reef, a charity that aims to protect the world’s marine life, offers a guide to choosing a reef-friendly sunscreen on their website.)

Paraben-Free

According to the FDA, parabens are widely used preservatives that extend the shelf life of products, and prevent growth of bacteria and fungi in cosmetics and other skin-care products such as sunscreen. Unfortunately, according to BreastCancer.org, because parabens can have weak estrogen-like properties, they may be linked to breast cancer and fertility issues. However, there is no scientific consensus on this issue. The FDA notes that at this time, there isn’t enough evidence to show that parabens have an effect on human health, though the agency is continuing to explore their potential hazards and possible alternative preservatives.

Photoaging

Unfortunately, this isn’t an app on your phone that shows what you’ll look like when you’re elderly — the definition is much less fun. “Photoaging is premature aging of the skin because of exposure to ultraviolet right,” Zeichner says. “This leads to the development of fine lines, wrinkles, crepey skin, brown spots, and broken capillaries.” Henry adds that another term for photoaging is “dermatoheliosis,” noting it can destroy the collagen in your skin and contribute to the formation of fine lines [and] wrinkles.

Photo Stable

When you see the words “photo stable” on a sunscreen label, know that the product will remain stable in UV light. “The main purpose of a sunscreen formula is to protect our skin from the damaging UV rays emitted by the sun,” says Thaggard. “If a sunscreen formula is not photo stable, it means that its protective properties start to diminish and become less effective in the presence of sunlight, therefore not adequately providing the UV protection you’re relying on it for.”

Physical Sunscreen

The term “physical sunscreen” is interchangeable with “mineral sunscreen,” says Henry. Both indicate a product contains ingredients such as zinc oxide and titanium dioxide and work by physically deflecting the sun’s rays from your skin (rather than absorbing them).

Retinyl Palmitate

Retinyl palmitate is a combination of retinol and palmitic acid, a fatty acid, according to Paula’s Choice. Per a study published in February 2016 in Biomedical Nanotechnology, it helps improve elasticity of the skin and combat wrinkles by ramping up collagen production. While the ingredient may make you more sensitive to the sun (as retinol is known to do, per the Skin Cancer Foundation), Paula’s Choice notes the ingredient is generally safe for use.

Reef-Friendly

If you’re sunbathing on a rooftop in New York City, certain eco-conscious concerns may seem less relevant. But if your next vacation involves snorkeling, you may want to select a reef-friendly sunscreen. According to a study published in February 2016 in the Archives of Environmental Contamination and Toxicology, oxybenzone and octinoxate are among the ingredients that can induce bleaching and affect coral’s ability to reproduce by harming or killing coral larvae. Other non-reef-friendly ingredients include nanoparticles like zinc oxide or titanium dioxide, 4-methylbenzylidene camphor, octocrylene, para-aminobenzoic acid, methyl paraben, ethyl paraben, propyl paraben, butyl paraben, benzyl paraben, and triclosan, according to nonprofit research organization Haereticus Environmental Laboratory. Some popular travel locations, such as Aruba, Hawaii, and the U.S. Virgin Islands, have even banned sunscreens containing non-reef-friendly ingredients, as Condé Nast Traveler points out.

Sand-Resistant

This term is a misnomer because sand is impossible to resist. (Think of everything you’ve ever eaten at a beach that had sand in it!) But “in theory,” Henry says, “if a sunscreen is thicker, it is more likely to have sand adhere to it, which might decrease its SPF. So some sunscreens offer smoother formulations, which tend to be a little bit more sand resistant than thicker sunscreens.”

Sensitive Skin

Zeichner says that when a sunscreen label says it is formulated for “sensitive skin,” that means it may be safer for people with skin conditions such as eczema or rosacea, or those prone to acne. It’s worth noting that the FDA does not define this term for sunscreen (or any skin-care products). But the AAD recommends opting for a physical sunscreen that contains titanium dioxide or zinc oxide if you have sensitive skin, as they are less likely to cause irritation. The organization also suggests choosing skin-care products labeled “fragrance-free,” rather than “unscented” (which can still contain potentially irritating chemicals to neutralize fragrance).

SPF

These three crucial letters stand for "sun protection factor." SPF can range from 2 to more than 50. Per the FDA, this number indicates the amount of UV radiation from which your sunscreen can protect you; the higher the number, the more protection it offers. The AAD recommends choosing a sunscreen with at least SPF 30. But when in doubt, always go for a higher SPF: An EWG study published in Photodermatology, Photoimmunology, & Photomedicine in October 2021 suggested that, based on computer modeling of UV protection in common sunscreen products, the actual UV protection of these sunscreens could be significantly lower than what’s labeled.

Sports

When you see the word “sports” on a label, it’s important to know that the FDA has not defined this term for sunscreen. It usually means that the sunscreen will stay on wet skin for either 40 or 80 minutes, according to the AAD. (You may also see it labeled as “water-resistant” or “very water-resistant.”) Depending on how much you sweat and whether you’re drying yourself with a towel, you’ll need to reapply these products either every 40 or 80 minutes. (If you’re working out in the sun for more than 80 minutes, we applaud you.)

Tinted

If you’re looking for some coverage alongside your SPF protection, look no further than tinted sunscreen. As Harvard Health Publishing notes, tinted sunscreens combine broad-spectrum mineral UV filters with pigments to deliver a product that’s equal parts makeup and skin care. But that’s not all they can do: A review published in April 2020 in the Journal of the American Academy of Dermatology noted that tinted sunscreens may be especially beneficial in protecting against hyperpigmentation disorders such as melasma (patches of darkened skin most commonly found in women, per the AAD).

Titanium Dioxide

According to the EWG, titanium dioxide is one of two mineral-based active ingredients (along with zinc oxide) that the FDA permits in U.S. sunscreen products. It is a physical blocker that decreases UV skin penetration by creating a barrier on the skin.

UV Light

UV is short for ultraviolet, and UV light is a form of radiation emitted by the sun that is invisible to the human eye, according to NASA.gov. It is a known carcinogen, says Henry, meaning it can cause cancer. Indeed, most skin cancers result from excess exposure to UV in sunlight, per the American Cancer Society.

UVA

UVA stands for ultraviolet A, notes the Skin Cancer Foundation. While these rays are less intense that UVB (see below), UVA accounts for up to 95 percent of the UV radiation reaching the earth’s surface. “I call UVB burning and UVA aging,” says Henry, who explains that because UVA penetrates a bit deeper than UVB, it plays a major part in skin aging and wrinkling.

UVB

Compared with UVA rays, ultraviolet B rays are shorter and more intense. UVB damages the skin’s more superficial epidermal layers, causing skin reddening and sunburn, and for this reason, they play a key role in the development of skin cancer, according to the Skin Cancer Foundation. “UVB is what gives kind of the characteristic, classic burn that we attribute to chronic sun exposure,” says Henry, who says to be especially careful about UVB between 10 a.m. and 4 p.m, when these rays are their strongest.

Water-Resistant, Very Water-Resistant

Per the AAD, water resistant sunscreen will stay effective on the skin for 40 minutes in the water. Very water resistant sunscreen will stay effective on the skin for 80 minutes in the water. You’ll need to reapply after this time. (You might also see water resistant sunscreen labeled as “sports” sunscreen, since it’s designed to withstand some sweat and swimming.)

Waterproof Sunscreen

According to the AAD, there is no such thing as a waterproof sunscreen. Because sweat and water remove sunscreen from our skin, the FDA no longer allows this term on product packaging. You can opt for a water-resistant sunscreen, which will stand up to sweat and water for longer than regular sunscreen, but you’ll still need to reapply it after time spent in the water.

Zinc Oxide

According to the EWG, zinc oxide is one of just two active ingredients (the other one is titanium dioxide) that the FDA has determined to be safe and effective in sunscreens.

Additional reporting by Emily Rekstis.