Picking up a few bug bites used to be one of summer’s rites of passage. It’s not so innocent these days: shielding yourself from ticks and mosquitoes is just as important as wearing sunscreen. “People used to hate to wear [insect] repellent, or say, ‘Oh, I don’t care about getting bitten,’” says Walter S. Leal, PhD, a chemical ecologist and professor of entomology at the University of California, Davis. Now, many experts warn that mosquitoes carrying the Zika virus may reach certain parts of the United States. Plus, West Nile has been reported in all 48 continental states. What’s more, it’s not just mosquitoes we need to be guarding against; ticks are a concern, too. The Centers for Disease Control and Prevention estimates Lyme disease rates have been rising steadily for at least three decades, and ticks can also carry other potentially fatal diseases.

Before you rush to the drugstore to stock up on bug spray, here are a few things you need to know.

Keep your eyes peeled for EPA registration

“Of the 20,000 products out there to supposedly repel insects, many don’t work at all,” says Immo A. Hansen, PhD, a molecular vector physiology expert at New Mexico State University whose team recently published a study of repellent efficacy in the Journal of Insect Science. So when can you actually believe what the label says? Most skin-applied insect repellents must be registered by the Environmental Protection Agency before they reach the market; if you see an EPA registration number on a product label, you know that it’s been tested for safety and effectiveness. Better yet, as of this year, some products now have a black-and-yellow repellency awareness graphic which clearly states how long they have been proven to repel mosquitoes and ticks; that symbol means the company has provided the EPA with scientific data to support their claims.

Don’t be afraid of DEET

“People have the notion that DEET is synthetic and therefore it’s not a good thing,” says Leal. “But it’s so effective and so good that it’s lasted for more than six decades.” No other product has been tested for safety and effectiveness in repelling insects more than DEET, Leal says, and reports of health risks have largely been overblown. Plus, it’s the only type of repellent that the CDC recommends for tick protection. It’s safe to use on children 2 months and older.

“If you’re going to stay outside and you don’t want to bother with reapplying many times, I think DEET is the best thing we have on the market,” Leal says. For most purposes, formulations containing 20% DEET are effective, says Leal.

There is a downside to DEET: it has a pesky plasticizing effect that can damage fabrics, surfaces, and materials. It won’t harm cotton, wool, or nylon, but materials like rubber, plastic, leather, vinyl, spandex, and even auto paint are fair game, so be sure to wash your hands thoroughly after handling it.

Picaridin is also a good choice

Picaridin, another synthetic repellent, is also effective at keeping mosquitoes at bay for extended periods of time. (It may also protect against ticks, but the CDC recommends sticking to DEET if you’re going to be in a tick-heavy area.) In a recent Consumer Reports spray-off, a product with 20% picaridin repelled mosquitoes for 8 hours and was considered the best repellent overall. While it lacks DEET’s distinguished history (it’s too new for us to know of potential long-term health risks—it was just approved for sale in the U.S. in 2005, whereas DEET has been around since 1946), it won’t damage your belongings the way DEET can. Stacy Rodriguez, Hansen’s colleague at the Molecular Vector Physiology Laboratory at New Mexico State University, is investigating the efficacy of repellents containing picaridin this summer.

Candles and bracelets don’t work

Rodriguez has studied devices like oil of lemon eucalyptus bracelets and ultrasonic devices, and found none of them to be effective against mosquitos. “At this point in my research, I would strongly suggest spray-on repellents,” she says. You can also forget about citronella candles—research shows don’t work any better than regular candles at keeping bugs at bay. If keeping bugs out of your backyard is your goal, then your best bet is to eliminate standing water, where mosquitoes thrive.

There is one natural option, but it’s not necessarily safer

Synthesized oil of lemon eucalyptus (OLE) extract (not the essential oil) is also an effective mosquito repellent. While it’s plant-based, it isn’t necessarily safer than lab-based repellents (and it doesn’t repel ticks). The FDA cautions that OLE should be avoided for children under the age of 3, as it can cause temporary injury to the eyes.

Which repellent is right for you?

Plug your criteria (insect, protection time, active ingredient of choice, and so on) into the EPA’s search tool, or consider one of these formulations.

Ben’s 30% Spray

Active ingredient: DEET

This water-based formulation won’t evaporate as quickly as alcohol-based formulations do, and it won’t take up valuable real estate in a hiker’s backpack.

To buy: $5; amazon.com

Off! Deep Woods

Active Ingredient: DEET

Aerosol cans take up space, but they make it easy to be sure you’re covering every last bit of exposed skin. This product contains 25% DEET, and the powder-dry formula never feels sticky or greasy. It provides up to 8 hours of protection from mosquitoes and ticks.

To buy: $9; amazon.com

Repel Sportsmen 30% DEET Wipes

Active ingredient: DEET

These wipes promise up to 10 hours of protection from insects, though Leal cautions that repellent needs to be reapplied more frequently when we swim or get especially sweaty. Some “sporty” products offer formulations of up to almost 100% DEET—and are more than anyone would need, he notes. According to the CDC, concentrations of over 50% provide no added protection.

To buy: $6; amazon.com

Sawyer Controlled-Release Repellent Lotion

Active ingredient: DEET

The time-controlled release of active ingredients in this lotion provides protection for up to 11 hours—perfect for a long hike.

To buy: $7; amazon.com

Sawyer Picaridin 20%

Active ingredient: Picaridin

This product provides up to 12 hours of protection, and it’s small enough to be carried on a plane—which is key, according to Leal. “I take a little bottle [of repellent] in my carry-on and have a bigger one checked in my bag when I travel,” he says. “You don’t want to risk arriving [at a mosquito-infested destination] and not be able to find any repellent on the shelves.”

To buy: $9; amazon.com

Natrapel 20%

Active ingredient: Picaridin

Natrapel promises 8 hours of protection and a light floral scent; like other picaridin formulations, it’s safe to spray on clothing as well. (Never apply repellent under clothing; “there’s no benefit to that,” Leal says. “Focus on areas of skin that are exposed.”)

To buy: $10; amazon.com

Cutter Advanced Wipes

Active ingredient: Picaridin

Wipes boast both portability and ease of use for facial application; repellent should never be sprayed directly on the face.

To buy: $6; amazon.com

Cutter Lemon Eucalyptus

Active ingredient: Oil of lemon eucalyptus extract

This spray provides up to 6 hours of protection. That’s probably all the protection you need for spending an afternoon in a backyard setting, Hansen says. “Someone hiking in the Everglades, by contrast, would probably want to reapply every 4 to 6 hours.”

To buy: $8; amazon.com

REPEL Lemon Eucalyptus

Active ingredient: Oil of lemon eucalyptus

Spritz on this bug spray and repel mosquitoes for up to 6 hours.

To buy: $11; amazon.com

Off! Botanicals Wipes

These super-portable, individually wrapped wipes provide 2 hours of protection, so be sure to pack an extra.

To buy: $5; amazon.com

This article originally appeared on Health.com

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