Sorry, That Viral Mosquito Repellent Taking Over TikTok Doesn’t Really Work

My part of the Midwest has been experiencing rainy day after rainy day this summer, which has been great for my raised garden bed — and for all the mosquitoes in my backyard. While last summer’s drought nearly wiped out the mosquito population in my shady backyard, this summer’s influx of rain has allowed them to completely take over.

I am somehow, scientifically or not, a total mosquito magnet. Every time I walk outside they seem to immediately find me! That’s why I’ve been on the hunt for ways to keep them off my body (and better yet, off my patio) so I can actually enjoy my backyard this summer. My research led me to a hack that’s completely taken over TikTok: burning coffee grounds to help repel mosquitoes.

You can find video after video outlining this mosquito repelling hack, with some relying on matches and others using a lighter to start the burning. The materials are cheap, and the process seems easy enough — just set the coffee grounds alight and you’ll be mosquito-free. So here’s the real question: does burning coffee grounds to repel mosquitoes actually work?

Unfortunately for me (and for you), pros say this hack isn’t all it’s cracked up to be. Emma Grace Crumbley, an entomologist for the pest control company Mosquito Squad, says that there aren’t actually any scientific studies to support the idea that burning coffee grounds can repel mosquitoes. While some research suggests mosquitoes are repelled by the scent of brewed coffee, it’s more or less inconclusive.

Becca Tellar, head of customer experience at pest control company Pestie, agrees. “Some people may observe a decrease in mosquito activity when burning items like coffee grounds,” she says. “However, some studies suggest that it’s actually the smoke, rather than the smell, that deters mosquitoes, and we would love to see more studies in this area.” The same can be said for citronella candles, she adds.

So, is there harm to trying out the coffee trick? Probably not, but don’t expect it to solve your mosquito problem. Furthermore, depending on where you live, it could cause bigger problems. “It should be noted that burnt coffee grounds may attract bears … so be aware of your region’s wildlife before taking on this hack!” Crumbley says.

Both Tellar and Crumbley say the best thing you can do to battle mosquitoes is to prevent them from breeding in the first place. “Experimental ‘hacks’ like this are not long-term solutions to pest problems,” Crumbley says. She advises keeping your yard tidy to eliminate areas where mosquitoes can live and breed.

Tellar adds that you should address any standing water ASAP. “Eliminate standing water sources like kids’ pools, pet water bowls, and puddles from sprinklers around the yard,” she advises.

As for keeping mosquitoes off your patio, you’ll likely have better luck using an outdoor fan (since the bugs can’t fly against the breeze) or a mosquito repellent made to address a large area.