Sunscreen Glossary: Guide for Decoding Every SPF Term You Need to Know

Sunscreen Glossary

Flip-flops, tank tops, days at the beach and backyard barbecues. These are some of the great things about summer and why most people love the sun. And there are more fundamental reasons.

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 cheers us up when we’re feeling down. Meanwhile, other research links sunlight to reducing tumor growths, and it may play a part in treating some inflammatory diseases — yet too much exposure to the sun can increase your risk for potentially deadly skin cancer.

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 woefully in the dark about some basic facts

Labels are confusing. 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.  


Because sunscreens are classified as over-the-counter drugs in the United States, the 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.


Antioxidants are compounds that absorb energy from free radicals and prevent them from causing damage to the skin.


According to the U.S. National Library of Medicine, Avobenzone is a topical, broad-range UV protector that blocks UVA I, UVA II, 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 one of 12 sunscreen ingredients on which the FDA is currently conducting further research.


According to the American Association of Dermatology, the FDA has no strict definition for this term. But in general, when you see “baby” on sunscreen packaging it typically (though not always) means that it’s a mineral or physical sunscreen.

Broad Spectrum

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.


Chemical ingredients that absorb UVA and UVB radiation are found in most broad-spectrum sunscreens. 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. Chemical sunscreens contain compounds that absorb UV light and prevent it from penetrating into the skin.

Dermatologically Tested  

This term indicates that a dermatologist has been in charge of product tolerance tests, carried out with voluntary test subjects.


The term ‘fragrance’ can include a blend of nearly 4,000 ingredients in sunscreens. 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. 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. Safest bet, go with fragrance free.

Free Radicals

Free radicals are molecules that have high levels of energy. In the skin, they can damage cells’ DNA and weaken collagen, can advance skin aging and cause skin cancer.  According to the EWG’s 2019 report, 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.


This term suggests that a sunscreen is less likely to cause allergic reactions. This is 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.

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.


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, which is formulated with oil-absorbing ingredients.


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


Noncomedogenic means a sunscreen has ingredients that are less likely to cause breakouts by clogging your skin pores.

Oil Free

A product that says it is oil free should be free of any oils. 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 filters such as cinnamates, salicylates, and benzophenones absorb UV radiation and convert it to a small amount of heat. Yet among dermatologists, this term is controversial. Some dermatologists, for example, refer to chemical sunscreen as organic and mineral sunscreens as nonorganic.


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.


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. (Spoiler alert: Not everyone likes rubbing mold on their faces.) Unfortunately, according to, because parabens can have weak estrogen-like properties, they may be linked to breast cancer and fertility issues. But there is no scientific consensus on this issue. The FDA notes that at this time, there isn’t enough evidence “showing that parabens as they are used in cosmetics have an effect on human health,” though the agency is continuing to explore their potential hazards and possible alternative preservatives.


Photo aging is premature aging of the skin because of exposure to ultraviolet light.


Photo stable on a sunscreen label indicates that the product will remain stable in UV light.

Physical Sunscreen

The term physical sunscreen is interchangeable with mineral sunscreen. Both indicate a product contains ingredients such as zinc oxide and titanium dioxide. Mineral sunscreens 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 the skin-care product company Paula’s Choice. It helps improve elasticity of the skin and combat wrinkles by ramping up collagen production.


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 affect coral’s ability to reproduce by harming or killing coral larvae.

Sand Resistant

Some sunscreens offer smoother formulations, which tend to be a little bit more sand resistant than thicker sunscreens.

Sensitive Skin

This is formulated for “sensitive skin,” which means it may be safer for people with skin conditions such as eczema or rosacea, or those prone to acne. The FDA does not define this term for sunscreen, per the ADA, but in general it suggests the product contains one or both of the active ingredients titanium dioxide and zinc oxide, and doesn’t contain fragrance, oils, PABA, or active ingredients found in chemical sunscreens, which can irritate sensitive skin. 


These three crucially important letters stand for “sun protection factor.” SPF can range from 2 to more than 50. This number indicates:

  • The percentage of UVB that a sunscreen can block
  • How long it will protect you from the sun.

To give you a sense of what these numbers mean: SPF 15 blocks 93 percent of UVB. Current recommendations from the American Academy of Dermatology is to use a sunscreen with at least SPF 30 protection.

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. Ultraviolet light is a form of radiation emitted by the sun that is invisible to the human eye, according to It is a known carcinogen. What the AAD recommends is SPF 30 for daily use and SPF 50 if you’re going to be outside for more than an hour.


UVA stands for ultraviolet light. 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.


Ultraviolet B rays are shorter and more intense. UVB damages the skin’s more superficial epidermal layers, causing skin reddening and sunburn. For this reason, they play a key role in the development of skin cancer.


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, says the ADA. 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.

Water Resistant 40

This sunscreen will remain effective for up to 40 minutes of exposure to (or submersion in) water, notes the ADA.

Waterproof Sunscreen

According to the ADA, 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.

Very Water Resistant 80

This sunscreen will remain effective for up to 80 minutes of exposure to (or submersion in) water, per the ADA.

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.

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