One of the upshots of the 2016 Zika outbreaks is that there are now many more insect repellents to choose from.
According to a recent study by scientists at New Mexico State University, the number of repellent products available on Amazon has nearly doubled (from 13,000 products to around 25,000) in recent years.
This sheer number of options presents consumers with a double-edged sword: It's good to have choices, but it's not always easy to tell what works and what doesn't.
"The recurrent outbreaks of dengue, chikungunya, and Zika have created a large market for a variety of mosquito repellent and control products," says Immo Hansen, a scientist who studies insect-borne diseases at New Mexico State University. "But in many cases, the claims made by the vendors of these products are exaggerated or outright false."
Joe Conlon, an entomologist with the American Mosquito Control Association, a trade group, said that area repellents—products that claim to create an insect-free bubble around the user—can be particularly problematic. "They have limitations," he says. The AMCA advises consumers to stick with Environmental Protection Agency-registered products, and says that no product is more effective than DEET.
To help separate the good stuff from the not-so-good, we've compiled a quick list of products that you can skip.
It sounds like such a good idea: Use a "natural" mosquito repellent, with an active ingredient like clove or lemongrass or rosemary oil, and avoid the ones containing chemicals, such as DEET.
But here's the problem: Natural repellents are regulated differently than other repellent products. Because the EPA deems the chemicals they contain harmless, the agency does not evaluate them for effectiveness. Because of that loophole, companies that sell those repellents don't have to prove that they actually work. And our testing indicates that, in fact, they don't work.
Most of the plant-based repellents CR has tested lasted just 1 hour or less against the Aedes aegypti mosquito—the kind that can spread Zika, yellow fever, dengue, and chikungunya.
Daniel Fabricant, Ph.D., president and CEO of the Natural Products Association, told Consumer Reports that natural repellents vary in their effectiveness the same way that other repellents do.
The Centers for Disease Control and Prevention and the EPA both say that DEET is safe when used properly, even for pregnant women. Our experts agree, though they recommend sticking to products that contain 15 percent to 30 percent DEET.
These wearable repellent devices are marketed as being safer, because you don't have to rub anything on your skin.
But Consumer Reports has tested wristband products and found them to be ineffective: When our testers stuck their arms into a cage full of mosquitoes while wearing one of two wristbands—the Coleman Naturals Insect Repellent Snap Band or the Super Band Wristband—the bugs started biting immediately.
Last May, the Federal Trade Commission fined another wristband maker, Viatek, $300,000 for deceptive marketing of its Mosquito Shield Bands. The commission says the company's claims—that the bands protect against mosquitoes—were not backed up with scientific evidence.
Ultrasonic devices claim to emit high-frequency sounds that are too high for humans to hear but are just the right frequency to drive pests, including mosquitoes, away. The trouble is, there's no proof that they work.
The Federal Trade Commission has investigated several sonic repellent makers for false advertising. In 2016, the New York Attorney General's Office sent cease and desist letters to the makers of two specific brands of sonic repellent—STAR Ultrasonic Pest Repeller and iGear iGuard 2.0 Ultrasonic Insect Pest Repeller. "Numerous scientific studies show that [these devices] don't repel mosquitoes and may even attract mosquitoes," the attorney general said.
Clip-on repellents may seem like a great idea, because they allow you to avoid rubbing chemicals directly onto your skin. But the CDC says that wearable foggers "have not been adequately evaluated for their efficacy in preventing vector-borne diseases."
Our own testing of one such product—the Off! Clip-On repellent, a device that attaches to your waistband and then uses a fan to circulate the chemical metofluthrin into the air around you—found that it offered far less protection than our best-performing spray-on repellents.
Perhaps most important, Consumer Reports also has concerns about the safety of the Off! Clip-On because it uses the chemical metofluthrin, which is classified by the EPA as a neurotoxin and as a potential carcinogen.
Our tests of two area repellents—citronella candles and a battery-powered diffuser that blows out the chemical geraniol—showed they were ineffective at keeping mosquitoes away. An oscillating pedestal fan set on high worked much better: It cut mosquito landings by 45 to 65 percent, at least among people close to it.
But your best bet is doing things that discourage mosquitoes from breeding in the first place. Keep your yard free of containers filled with water, such as gutters, birdbaths, tires, wheelbarrows, wading pools, and swimming pool covers. Clear away ivy and decaying leaves, because mosquitoes like cool, dark places. And because ticks like tall grass and lots of shade, it's best to keep your lawn mowed and free of leaves and other debris (read our lawn mower buying guide).
For a list of products to try instead, see our insect repellent buyer's guide.