Is DEET Really Your Best Choice? We Explored Your Options for Insect Repellent.

No one wants to spend long evenings huddled in a tent hiding from mosquitoes. But choose the wrong insect repellent, and this sad scenario could be in your future.

After all, mosquitoes, ticks, and other biting insects aren’t just annoying—they can be dangerous, spreading diseases like Zika, West Nile, Alpha-gal Syndrome, and Lyme. Fortunately, the EPA has registered and approved a number of active ingredients in insect repellents that are both safe and effective when used correctly.

We spoke with Andrew Li, a research entomologist at the U.S. Department of Agriculture about which repellents are most effective and why you might want to reach for something different on your next excursion.

DEET

“There’s a misperception of DEET,” Li says. To be sure, it’s simultaneously the most well-known, best stocked, and most reviled insect repellent on the market. There’s no doubt that DEET is effective at repelling a wide variety of biting bugs, including mosquitoes and ticks, but it gets a bad rap. It feels greasy, smells terrible, and the fact that it can dissolve plastic, including some synthetic materials found in hiking gear, is enough to turn people off to the compound despite its efficacy and proven safety.

One thing everyone agrees on: DEET works. It’s effective for up 12 hours in some concentrations. It’s also safe to apply to skin and available in formulations from 10 percent to 100 percent. The higher the percentage, the longer it lasts and the less you need. Just don’t exceed 30 percent concentration if using it on children, says the American Academy of Pediatrics.

Picaridin

Picaridin might not be available in the as widely as DEET, but “it’s just as effective against mosquitoes in a like concentration,” says Steve McClure, who updated the section on insect repellent for the most recent edition of Mountaineering: The Freedom of the Hills. Unlike DEET, there’s no chance that picaridin will melt a hole in your gear. Plus, it doesn’t feel greasy or have that infamous chemical stench.

Picaridin repels mosquitoes, ticks, biting flies, and chiggers, and some formulations last as long or longer than DEET. But it might be mildly toxic to fish, so consider skipping that dip in the lake if you just coated yourself in picaridin. As with DEET, the higher the concentration in your repellent, the longer it will last. Concentrations around 30 percent will do the trick for most adventures.

IR3535

Although it might sound more like an alien compound designed to give you superpowers than repel insects, IR3535 is a proven solution to keep annoying blood-suckers away without causing skin irritation, which a minority of people experience with DEET. In fact, many studies put the compound on par with DEET for its ability to repel mosquitoes and ticks for long periods of time (8 to 10 hours and beyond). Plus: It’s odorless.

There aren’t as many options on the market, though, so you might have to do a little digging to find it on store shelves. You might find brands like Avon or Bullfrog locally, but you can also check Amazon or Walmart.

Permethrin

If you’d prefer not t0 apply bug spray directly to your skin, turn to permethrin, which McClure calls an essential part of a bug defense strategy. Especially effective at killing ticks, it also defends against mosquitoes as a contact repellent, meaning if a biting insect lands on a treated surface, permethrin will eliminate the threat.

The compound is strictly for treating clothing and non-waterproof gear—don’t spray it on your skin. Apply permethrin to clothing and gear, then let it dry. Permethrin will protect treated surfaces from ticks and mosquitoes for up to six weeks. Bonus: It’s odor-free after it dries and doesn’t leave a residue.

A note on cleaning: Machine washing will gradually reduce your treated clothing’s efficacy. The agitation from the washing machine deteriorates the permethrin because it scrapes and knocks the molecules off the fabric itself. Your best bet? Hand washing and air drying. Or, when using a conventional washer, turn on the gentle setting.

Herbal and Natural Remedies

The EPA has approved some formulations of oil of lemon eucalyptus and catnip oil to repel insects for 6 or 7 hours, but think twice before heading into the backcountry with other herbal or natural remedies.

“I won’t say they’re not effective at all,” says Li, though they often haven’t been adequately tested. He adds, “Most don’t meet EPA approval.”

That includes wristbands, patches, and citronella candles; although these are common on the market, some tests have shown they don’t repel mosquitoes at all. Weigh the risks and rewards before you take a gamble on repellent without proven efficacy, and look for a repellent that’s been thoroughly vetted and approved by the EPA.