As a result of the Zika virus outbreak in 2016, there are now more insect repellents to choose from.

According to a recent study by scientists at New Mexico State University, the number of insect repellent products available on Amazon has almost doubled in recent years (from 13,000 to approximately 25,000).

So many choices provide consumers with a double-edged sword: it is good to have choices, but it is not always easy to distinguish which ones are effective and which ones are ineffective.

“The repeated outbreaks of dengue fever, chikungunya fever and Zika virus have created a huge market for various mosquito repellent and control products,” said Imogen Hansen, a scientist who studies insect-borne diseases at New Mexico State University. "But in many cases, the claims of the suppliers of these products are exaggerated or completely wrong."

Joe Conlon, an entomologist at the trade organization American Anti-Mosquito Association, said that regional insect repellents — products that claim to produce insect-free bubbles around users — can be particularly problematic. "They have limitations," he said. AMCA advises consumers to insist on using products registered by the Environmental Protection Agency and stated that no product is more effective than DEET.

To help distinguish the good from the bad, we have compiled a quick list of products that you can skip.

This sounds like a good idea: use "natural" mosquito repellents that contain active ingredients such as clove, lemongrass, or rosemary oil, and avoid chemical mosquito repellents such as DEET.

But the problem is that the regulation of natural insect repellents is different from other insect repellent products. Since the EPA considers the chemicals contained in them to be harmless, the agency will not evaluate their effectiveness. Because of this loophole, companies that sell these insect repellents do not have to prove that they actually work. Our tests show that, in fact, they do not work.

Most plant insect repellents tested by CR only last an hour or less for Aedes aegypti, which can transmit Zika virus, yellow fever, dengue fever and chikungunya.

Dr. Daniel Fabricant, President and CEO of the Natural Products Association, told Consumer Reports that the effects of natural insect repellents are the same as other insect repellents.

Both the Centers for Disease Control and Prevention and the US Environmental Protection Agency have stated that DEET is safe if used properly, even for pregnant women. Our experts agree, but they recommend sticking to products containing 15% to 30% DEET.

These wearable insect repellent devices are advertised as safer because you don't have to rub anything on your skin.

But Consumer Reports has tested wristband products and found that they are invalid: when our testers wear one of the two wristbands-Coleman Naturals Insect Repellent Snap Band or Super Band Wristband, when our testers put them on When his arm stretched into the cage full of mosquitoes, the mosquitoes began to bite people immediately.

In May of last year, the Federal Trade Commission imposed a fine of $300,000 on another wristband manufacturer, Viatek, for deceptive marketing of its Mosquito Shield Bands. The committee stated that the company's claims that these bands can prevent mosquitoes are not supported by scientific evidence.

Ultrasonic equipment claims that the high-frequency sound emitted is too high for humans, but it is the correct frequency to repel mosquitoes and other pests. The problem is that there is no evidence that they are effective.

The Federal Trade Commission investigated the false advertising of several manufacturers of sonic repellents. In 2016, the New York Attorney General's Office issued a suspension and termination letter to the manufacturers of two specific brands of sonic repellents-STAR Ultrasonic Pest Repeller and iGear iGuard 2.0 Ultrasonic Insect Pest Repeller. The Attorney General said: "A lot of scientific research has shown that [the devices] will not repel mosquitoes and may even attract mosquitoes."

Clip-on insect repellents seem to be a good idea because they allow you to avoid rubbing chemicals directly onto your skin. However, the CDC stated that wearable nebulizers "have not been fully evaluated for their effectiveness in preventing vector-borne diseases."

We tested one such product ourselves-Off! Clip-On insect repellent is a device that attaches to your belt and uses a fan to circulate the chemical methfluthrin into the air around you-found that it provides far less protection than our best-performing spray insect repellent Agent.

Perhaps most importantly, Consumer Reports is also concerned about the safety of Off! Clip-On Because it uses the chemical mefluthrin, the EPA classifies it as a neurotoxin and a potential carcinogen.

Our testing of two regional insect repellents—citronella candles and battery-powered diffusers that blow out the chemical geraniol—showed that they were not effective in repelling mosquitoes. A swing base fan set up at a high place is better: it reduces mosquito landings by 45% to 65%, at least among people approaching it.

But the best way is to first take measures to prevent mosquitoes from reproducing. Keep your yard clear of water-filled containers, such as drains, birdbaths, tires, trolleys, shallow pools, and swimming pool covers. Remove ivy and rotting leaves, because mosquitoes like cool, dark places. And because ticks like tall grass and lots of shade, it's best to keep the lawn mowed and free of leaves and other debris (read our lawn mower buying guide).

For a list of trial products, please refer to our insect repellent buying guide.

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