A good sunscreen is one you’ll wear…and wear often. But the ideal sunscreen not only feels good to wear, it also provides ample protection against UVA and UVB rays, is affordable, and is safe for both humans and the environment. As it turns out, that’s a tall order. If you’re looking for the best sunscreen—or just trying to understand how to read a sunscreen label—you’ve come to the right place.

A quick guide to sunscreen terms

Scroll down for more information on each term.

Why, when, and how should I wear sunscreen?

Protecting your skin from ultraviolet (UV) rays helps prevent sunburn, premature aging, and skin cancer (the most common type of cancer). Avoiding the sun when it’s brightest (usually between 10 a.m. and 2 p.m.), seeking shade, and wearing sunglasses, a wide-brimmed hat, sun-protective clothing, and sunscreen should all be tools in your sun-safety toolbox.  

And sun protection should be part of your routine no matter the time of year or the amount of time you’ll be outside. Even in the winter, when most of your body is covered, your face is likely still exposed to UV light. You should also wear sunscreen (or cover up) even if you’re just running errands or walking to and from the car. Short bursts of UV light add up. 

If you do use sunscreen, odds are, you’re not using nearly enough. Studies show that people tend to apply 20 to 50 percent as much sunscreen as they should. If you’re wearing a bathing suit, for example, you need about a shot glass’s worth to cover your body. And you need to reapply the same amount every two hours no matter what SPF you’re using…and more often if you’ve been sweating or swimming. 

What are ultraviolet rays?  

UV light that reaches the Earth’s surface is made up of UVA and UVB rays. Roughly 95 percent is UVA, which penetrates clouds, window glass, and the deep layers of skin. It causes premature skin aging like dark spots and wrinkles. UVB, on the other hand, is partially absorbed by clouds, doesn’t penetrate window glass, and doesn’t penetrate as deeply into the skin. UVB is primarily responsible for sunburn. (Helpful hint: UVA = aging; UVB = burns.) Nevertheless, both cause skin cancer.  

UVB rays are strongest around midday, but UVA rays are present as long as there’s daylight. That’s why it’s important to protect your skin even in the early morning or late afternoon. 

What is SPF?  

SPF—or sun protection factor— tells you how much protection a sunscreen provides from UVB rays. SPF 30 blocks 97 percent of UVB rays. SPF 60 blocks about 98 percent. (No sunscreen blocks 100 percent.) The American Academy of Dermatology recommends sunscreens with an SPF of at least 30.  

But SPF doesn’t tell you how much protection a sunscreen provides against UVA rays. So high SPF sunscreens may give you a false sense of security, leading you to stay in the sun longer because they’re protecting you from sunburn-causing UVB rays. That can overexpose you to the sun’s UVA rays.  

What does broad spectrum mean? 

To get at least some UVA protection, you need a sunscreen that’s labeled “broad spectrum.” The FDA has proposed that all sunscreens with an SPF of 15 or higher provide broad spectrum protection and that UVA protection must increase as SPF increases in all sunscreens labeled “broad spectrum.” Until that proposal is finalized, “broad spectrum” means you’re getting some UVA protection, but nothing on the label will tell you how much. 

What are my options for active ingredients? 

A sunscreen protects you from the sun because it contains one or more compounds called “UV filters.” They broadly fall into two categories:   

• Mineral (sometimes called physical) UV filters largely work like a shield, sitting on top of your skin and deflecting and scattering UV rays. The mineral UV filters are zinc oxide and titanium dioxide.
• Chemical UV filters absorb UV radiation and convert it into a tiny amount of heat, which is then released from the skin. The most popular chemical UV filters approved in the U.S. are avobenzone, homosalate, octinoxate, octocrylene, octisalate, and oxybenzone.  

Are the active ingredients safe? 

Mineral UV filters sit atop the skin and are safe, says the FDA. They can be included in sunscreen at concentrations up to 25 percent. 

In 2020, the FDA found that all six popular chemical UV filters can be absorbed into the bloodstream. But that doesn’t necessarily mean they’re dangerous, and you shouldn’t avoid using sunscreens that contain them, stressed the FDA.  

What are the safety concerns? Some studies suggest that several filters—like avobenzone, oxybenzone, and octinoxate—can cause skin irritation or allergic reactions, though the risk appears to be low. Other studies have raised concerns that oxybenzone and homosalate may disrupt hormones.  

But more research is needed on those and other outcomes like cancer risk, fertility, and birthweight. There simply isn’t enough evidence to draw any firm conclusions. The FDA has asked companies for more safety data, which will take years to gather. 

Based on the evidence we have now, the potential harms of chemical UV filters don’t outweigh their benefits in protecting you from UV rays. But stay tuned. 

Is mineral sunscreen better? 

Since mineral UV filters aren’t absorbed, and the FDA considers them safe and effective, shouldn’t sunscreens that use zinc oxide or titanium dioxide be the obvious choice? 

Unfortunately, other issues plague mineral sunscreens. For one, many people find their consistency (which can be thick or sticky) unacceptable. And mineral sunscreens can leave a white residue on your skin. To combat that (and to improve UV-blocking performance), “nano” versions of zinc oxide and titanium dioxide have become more popular. (Nano means that the compounds are smaller than 100 nanometers across. For comparison, a human hair is 80,000 to 100,000 nanometers wide.) But nano compounds may pose threats to the environment (more on that below). 

Perhaps the biggest issue with mineral sunscreens is that many don’t live up to their labeled SPF, says Consumer Reports. “CR’s testing has never found a mineral sunscreen that came in at the top of the ratings,” reported Susan Booth, the magazine’s leader of sunscreen testing, in early 2025. “Most of them hover in the middle of the pack, or even lower.” Consumer Reports  rates sunscreens on a scale of 0–100 based on how well their SPF lives up to the labeled value as well as the amount of UVA protection they provide. Even CR’s highest-rated mineral sunscreen received a score of only 55 and provided only about 50 percent of its labeled SPF. (CR’s highest-rated chemical sunscreen received a score of 100 out of 100. To see their results, you’ll need a subscription.)  

To be fair, many chemical sunscreens also don’t live up to their labeled SPF in CR’s tests. But several promise—and deliver—top-notch coverage. 

If you prefer a mineral sunscreen because you want to minimize chemical exposure to yourself or the environment (or for any other reason), be extra diligent about applying enough and reapplying it often. 

What does “reef safe” mean? 

When you wear sunscreen while swimming, snorkeling, or surfing, its ingredients can make their way into the ocean. But even if you’re not headed to the beach, the type of sunscreen you use may still matter because it can wash off in the shower and eventually find its way into waterways. And there’s evidence that some UV filters can cause problems like coral bleaching (which makes coral more susceptible to disease and can harm the reef’s ecosystem), hormone disruption in marine animals, and impaired growth of marine plants.  

Those environmental concerns have led to bans on some UV filters in places like Hawaii and the U.S. Virgin Islands. 

But before you start shelling out money for “reef safe” or “reef friendly” sunscreens, there are a few things to know. For starters, the claims may not mean what you think because neither term is regulated.  

“Reef safe” often means that the sunscreen doesn’t include oxybenzone or octinoxate. That’s important because studies find that both can harm marine life like algae, snails, mussels, and coral. 

“Reef safe” may also mean that the sunscreen isn’t a “nano” zinc oxide or titanium dioxide formulation. Studies show that nano zinc oxide and titanium dioxide can harm freshwater and marine life like phytoplankton, crustaceans, mollusks, and coral. 

But even if a sunscreen has no oxybenzone, octinoxate, or nanoparticles, that’s no guarantee that it’s safe for reefs. Researchers have only scratched the surface when it comes to understanding the environmental effects of most UV filters. One thing is clear, though: No UV filter is known to be truly safe for reefs. 

So what should you do? 

• Remember that sunscreen is just part of your toolbox. That’s why you should cover up as much as you can. And when you’re swimming, wear a rash guard—clothing with built-in UV protection—over your swimsuit. That way, you can use far less sunscreen.
• Lotions are likely more environmentally friendly than spray sunscreens, which can land on the sand and easily wash into the water. By one estimate, roughly 55 percent of sprayed sunscreen ends up in the environment.
• The UV filters with the strongest evidence for harm to marine ecosystems are oxybenzone and octinoxate. Avoid them.
• Based on the current evidence, non-nano mineral sunscreens are the most environmentally friendly option. (There’s no surefire way to tell if a mineral sunscreen is non-nano. Some labels may tell you, but it’s not required. If in doubt, check the product’s website or contact the company.) 

Do I need a water-resistant sunscreen? 

If you’ll be swimming or sweating, look for a water-resistant sunscreen. It will retain its SPF value for either 40 or 80 minutes (the label will tell you which). 

Should I use a spray or lotion? 

All forms of sunscreen are effective as long as they’re applied correctly. Just make sure to use enough. 

While it’s easier to see where you’ve applied a lotion than a spray, some people prefer sprays. Just make sure you apply enough and rub it in. And never spray directly on your face. Spray on your hands, then rub your hands on your face (avoiding your eyes). 

Does sunscreen expire?  

Yes, sunscreen expires, though it has a long shelf-life. If you don’t see an expiration date on the bottle, it means the company has proven that the sunscreen is stable for at least three years.  

If you’re applying sunscreen as often and as generously as you should, though, a typical 8-to-12 oz. bottle shouldn’t last for more than one season. If you’re unsure how long you’ve had your sunscreen or if it separates into clumps, it’s time for a new bottle.  

How to dispose of the bottle? If it’s made of #1 or #2 plastic, it can go in your recycling bin. If there’s still a lot of sunscreen in the bottle, try to wipe it out and into the trash (don’t send it down the drain). Got a spray sunscreen to get rid of? Check to see if your local recycler accepts them. Many do. You may just need to remove the plastic cap first.  

Note: Sunscreen can degrade faster if it’s exposed to heat or direct sunlight, so don’t keep it in your car. Long day at the beach, pool, or park? Wrap your sunscreen in a towel, keep it in the shade, or toss it in your cooler.