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The Most Effective Tick Repellents for Humans (and Dogs), According to Science

Photo: Ron Erwin/Getty Images/All Canada Photos

As more and more people flock to the outdoors, it is extremely important to be wary of tick-borne diseases. And the summer months are when you’re most susceptible because “as the weather gets better, tick numbers rise,” according to Dr. Thomas Daniels, who studies ticks at Fordham University’s Louis Calder Center. Places to watch out for include wooded areas and patches with tall grass and bushes, explains Dr. Goudarz Molaei, research scientist and director of the CAES Passive Tick Surveillance program and associate clinical professor at the Department of Epidemiology of Microbial Diseases at Yale University’s School of Public Health. It’s also important to know that tick bites don’t just happen on the hiking trail. “Close to 75 percent of Lyme’s disease cases have been reported from bites that occur in people’s own backyards,” Molaei explains.

Jeffrey Hammond, of the New York State Department of Health’s public-affairs office, recommends doing “a final, full-body tick check at the end of the day, and also check children and pets” in order to protect against ticks and tick-borne illness. A proper tick check starts with examining your feet, then on to armpits, wrists, knees, and, yes, groin. “Ticks start low and crawl up,” adds Dr. Thomas N. Mather, director of the University of Rhode Island’s Center for Vector-Borne Disease and its Tick Encounter Resource Center. “So if they get to the top of your head, it’s not that they fell out of a tree. Instead, they’ve crawled all the way up your body.” But the best way to deal with a tick bite is to prevent it from happening at all. Fortunately, there are some solid, science-backed ways to prevent the pests from latching on. To find out which tick repellents actually work and which ones aren’t worth trying, we asked eight tick experts to explain tick science and share some of their favorite products for keeping them off humans and their pets.

Best pesticide-treated clothing for humans

According to Molaei, there are generally two types of chemicals that serve as the first line of defense against ticks: repellents, which can be applied directly to the skin, and pesticides, which can be applied to clothing. Mather, Molaei, and our other experts all recommended permethrin (the same chemical used in delousing shampoos like Nix), which acts as a “tick-killing agent,” according to Dr. Rick Ostfeld, a disease ecologist at the Cary Institute. And although using a chemical to deal with bugs can sound intimidating, permethrin is one of the most widely used agricultural chemicals, so, as Mather notes, “everyone is exposed to permethrin to some degree.” For day-to-day tick prevention, Mather counts on clothing that’s been treated with permethrin. “Most of it comes from a company called Insect Shield in North Carolina, and it can go through the wash about 70 times and still be effective,” he says. Dr. Scott Williams, who works at the Connecticut Agricultural Experiment Station’s Department of Forestry & Horticulture, adds, “The weave of the sock makes it difficult for the smaller ticks to navigate, which increases their time exposed to the permethrin, which kills more of them.” Since ticks start low and crawl high, permethrin-treated socks are a good first line of defense because the chemical can kill ticks in their tracks.

To fend off any ticks that may crawl as high as your torso, you can also get this treated lightweight pocket tee.

This treated hat will protect your scalp from both ticks and the sun.

Best tick-repellent clothing treatment

You can also treat your own clothing with permethrin using a spray. “For tick repellent for myself and my field crew, we soak our clothes in permethrin and allow them to dry before wearing them,” says Williams. But unlike pretreated clothing (which can be washed over and over and retain its tick-repelling ability), clothes you’ve sprayed with permethrin lose their ability to kill ticks after about six weeks or six washes (whichever comes first). Spraying your sneakers or hiking boots before going out into the woods is another solid tick-prevention technique, as is spraying gardening gloves, pants, shorts, or T-shirts.

But avoid applying it directly to your skin. That’s not because permethrin is unsafe; in fact, the concentration of permethrin on pretreated clothing is “well below what the EPA calls the daily dermal, no-observable-effect level,” says Mather, meaning it’s functionally nontoxic. It’s just that permethrin breaks down on your skin after 15 minutes, according to its manufacturer, so spraying it on your body rather than your clothes leaves you vulnerable.

Best tick repellents for humans

The CDC — along with six of our other experts — recommends DEET as an effective tick repellent. “The EPA suggests that any product with DEET should have a concentration between 20 and 30 percent of the active ingredient,” says Molaei. He does note that while DEET typically lasts for 12 hours against mosquitos, it will only remain effective against ticks for around eight hours maximum. “DEET can also not be combined with lotion or sunscreen, otherwise the efficacy of the product decreases significantly.” These towelettes from Off! are soaked in 25 percent DEET and come recommended by Strategist contributor Maureen O’Connor, who uses them to prevent “Quasimodo-like reactions” to mosquito bites, but they will also work against ticks. While you can opt for a spray, she says that the towelettes are “quick, easy, and can be deployed in a bathroom stall without anyone noticing.”

If you want something with the maximum concentration of DEET, O’Connor also recommends Repel’s towelettes, which contain 30 percent DEET.

Dr. Catherine Hill, a professor of entomology at Purdue University, says picaridin, an insect repellent that can be applied to the skin, is another effective way to ward off ticks. Ostfeld says it’s one of “the most effective repellents against black-legged ticks,” the carriers of Lyme disease, babesiosis, anaplasmosis, and Powassan virus in most of North America. And compared to products that contain DEET, which can feel overly oily on the skin, picaridin is “more pleasant aesthetically,” says Dr. Kirby Stafford, a medical-veterinary entomologist. “While DEET is considered a relatively safe product, picaridin has less toxicity in comparison, but it can occasionally cause an allergic reaction if it accidentally gets on your face or into your eyes” says Molaei.

Best botanical tick repellent

Though the CDC and EPA do recommend essential oils like garlic oil and lemon-eucalyptus oil as somewhat effective repellents of black-legged ticks in yards and on skin, Mather wouldn’t advise essential oils as your primary line of defense. “I’m hard-pressed to find any hard data on them,” he says, adding that in the few experiments he and his colleagues from other universities have run, the results haven’t been great for essential oils. In a test of lawn products, “The natural products were very poor at killing ticks compared to the standard products,” which included a type of permethrin. But if you want to double up, lemon-eucalyptus oil is readily available. Just don’t rely on it as your main tick repellent.

Best tick repellents for dogs

Best oral tick treatment

When Strategist writer Liza Corsillo interviewed a panel of veterinarians about the best tick treatments for dogs, every single one recommended Bravecto chews, an oral tick treatment. Bravecto works by releasing insect poison into your dog’s bloodstream — rest assured, it’s completely harmless for Fido — which eventually becomes absorbed into the tissue fluids under your dog’s skin. There, “it’s transferred to any biting ticks, which then become dead ticks.” Note that because this is prescription medication, you should always consult with your vet first. For instance, some oral tick preventatives, like Bravecto, are not recommended for dogs with a history of uncontrolled seizures, explains Corsillo.

Best topical tick treatment