Nothing kills our chill-out-in-nature vibe faster than becoming an all-you-can-eat buffet for mosquitos, ticks and other bloodsuckers. And beyond the maddening itchiness, insect bites can pass along serious disease too—even if you’re not vacaying somewhere tropical.
“While Canada does not have local transmission of insect-borne killers like malaria and dengue, there are infectious diseases spread by insects here that can ruin your summer,” says Dr. David Fisman, professor of epidemiology at the Dalla Lana School of Public Health, University of Toronto, pointing to West Nile virus (from infected mozzies) and Lyme disease (via deer ticks).
So what gets bugs to buzz off—without dousing your skin in irritating chemicals? Here’s what you should know about insect repellents—the good, the bad and the frankly useless.
Invented for the U.S. military in the ’40s, DEET still ranks most effective. In a study testing 16 bug repellents on particularly game volunteers, published in 2002 in the New England Journal of Medicine (NEJM), DEET-based repellents fared best, giving “complete protection for the longest duration.” DEET’s side effects—some minor (skin/eye irritation), others scary (seizures, other neurological symptoms)—make a lot of people leery. But serious reactions are very rare; they’re typically linked to repeatedly applying way too much or ingesting it. Even the Environmental Working Group says, “DEET is generally safer than many people assume.”
PICARIDIN (A.K.A. ICARIDIN)
Harder to find than DEET but considered a solid alternative, picaridin is a synthetic ingredient approved by Health Canada in 2012. It’s similar to a compound found in the black pepper plant. Picaridin is thought to be almost as potent as DEET, without the same pitfalls: it doesn’t irritate the skin and eyes; it’s not stinky; and it doesn’t come with a “potentially toxic” rep. In the U.S., where it’s been sold longer, a recent study found no reported cases of major side effects.
OIL OF LEMON EUCALYPTUS
If you want something botanically based, oil of lemon eucalyptus is pretty much the only option with serious scientific cred. The ingredient’s active compound is p-menthane-3,8-diol (PMD); look for it on the label. Don’t confuse this ingredient with unrefined lemon eucalyptus essential oil—it’s not the same thing. A new study of 11 bug repellents, reported this year in the Journal of Insect Science, ranked sprays with DEET and PMD as the most effective at keeping mosquitos at bay. Other research has found that oil of lemon eucalyptus is on par with low-concentration DEET (i.e., doesn’t last as long as high-concentration DEET, but still trusty).
OTHER PLANT OILS (E.G., SOYBEAN, CITRONELLA)
Despite being pitched as safer-for-you bug repellers, how well other plant oils work is murky at best. Some might do the job for a short while (sometimes as little as mere minutes)—if they work at all. An old NEJM study found that a soybean oil-based product curbed bites for about 1.5 hours. But a more recent study in the Journal of Insect Science observed that two natural bug sprays (one with soybean oil plus geraniol, and one with citronella) had “little or no” effect on deterring mosquitos. So if you’re relying on these ingredients? Use them where there’s no risk of catching anything serious.