Citronella Candles Don’t Really Work. Stop Buying Them.

Citronella — an essential oil distilled from dried cultivated grasses — has long been regarded as a “natural” mosquito repellent. Citronella oil is sold in many different forms, from tabletop candles and essential oil diffusers to tiki torches, all promising to keep pests at bay.

But the truth is there’s no indication that citronella candles provide more protection than any other candle-produced smoke. That’s because essential oils don’t offer as substantial an invisible shield as EPA-approved repellents like DEET and picaridin do.

A mosquito interprets the world through multiple chemical receptors, according to Laurence Zwiebel, a Cornelius Vanderbilt Chair in biological sciences and a professor of biological sciences and pharmacology at the University of Vanderbilt. And essential oils block only a limited number of those receptors. Zwiebel told Wirecutter writer Doug Mahoney he wasn’t certain that an essential oil that worked for one species would work across a range of others.

“Repellents such as picaridin and DEET, on the other hand, block a much wider number of receptors on a more consistent basis,” Doug explains his article on why essential oils are terrible bug repellents.

Though Citronella is the most ubiquitous of these so-called mosquito repellents, it isn’t the only one that doesn’t work very well. Here are a few more:

Bug zappers. Because of the irresistible lure of their light, bug zappers are incredibly effective at killing bugs,” Doug explains in his article on bug zappers. “The only problem: They aren’t killing the bugs that bother you.”

A study from the University of Delaware tracked six residential bug zappers over 10 weeks, and it found that of the 13,789 insects killed, only 31 were biting flies (including mosquitoes). “That’s a sad 0.22%,” Doug writes in the article.

Mosquito traps. While he was testing mosquito control gear, Doug found that mosquito traps don’t live up to their marketing claims. Joe Conlon, then technical advisor for the American Mosquito Control Association, told Doug that both propane- and UV-based traps will capture mosquitoes, but these traps are just not as attractive to the pests as humans are.

Repellent bracelets. Though some of these bracelets are indeed made with active ingredients that could be off-putting to mosquitoes, those repellents aren’t concentrated enough to have a wide-reaching effect. Mosquitoes will likely avoid the bracelet, but they still might land and bite you elsewhere.

Sound-based products. “At least 10 studies in the past 15 years have unanimously denounced ultrasonic devices as having no repellency value whatsoever,” Conlon wrote on the American Mosquito Control Association’s website (and cited in our guide to the best mosquito control gear).