Insect Repellent Buying Guide

We begin our insect repellent tests by applying a standard dose to a measured area of skin on our test subjects’ arms. (The dose is determined by the Environmental Protection Agency’s product testing guidelines.)

After 30 minutes, these brave volunteers place their arms into the first two of four cages of 200 disease-free mosquitoes for 5 minutes. Our testers watch closely to see what happens inside the cage, and they count every time a mosquito lands on a subject’s arm, uses its proboscis (its long mouth) to probe the skin in an attempt to find a capillary, or bites the subject’s arm and begins to feed—which the testers can tell by watching for the insect’s abdomen to turn from gray to red or brown.

After 5 minutes, the subjects withdraw their arms, then repeat the process by placing their arms into a second pair of cages of disease-free mosquitoes of a different species, for another 5 minutes. The subjects then walk around for about 10 minutes to stimulate sweating. They do that to mimic real-world situations in which users might be active while wearing repellent.

Half an hour later, this procedure is repeated and then again every hour after that until a repellent fails our test, or until 8 hours have passed since it was applied. We record a repellent’s failure after the first “confirmed mosquito bite”—meaning a bite that’s followed by another bite within the same 5-minute session or in the 5-minute session that immediately follows.

Be Wary of ‘Natural’ Repellents
Several makers of “natural” insect repellents (which typically contain essential plant oils such as cedar, citronella, clove, lemongrass, peppermint, or rosemary) claim that their products can help ward off mosquitoes, including those that carry the Zika virus. But our tests show that these active ingredients aren’t very effective, sometimes failing in our tests in under an hour.

Don’t Use Combination Sunscreen-Insect Repellent Products
We’re not fans of these combo products. Sunscreen should be reapplied every 2 hours, which could overexpose you to the chemicals in repellents. 

Proper application and use are essential, both for maximum protection and to avoid possible side effects, including skin or eye irritation. That means:

• Apply repellent only to exposed skin or clothing (as directed on the product label). Never put it on under clothing.
• Use just enough to cover and only for as long as needed. Heavier doses don’t work better and can increase risks.
• With wipes, use enough of them to cover all exposed skin with repellent. Look for a clear shimmer of fluid on the skin after wiping, and avoid sharing the same wipe with someone else.
• Don’t apply repellents over cuts, wounds, or irritated skin. When applying to your face, spray first on your hands, then rub it in, avoiding your eyes and mouth, and using sparingly around ears.
• Don’t let young children apply insect repellent. Instead, put it on your own hands, then rub it on. Limit use on children’s hands because they often put them in their eyes and mouths.
• Don’t use near food, and wash hands after application and before eating or drinking.
• At the end of the day, wash treated skin with soap and water, and wash treated clothing in a separate wash before wearing again.
• If you’re planning to use repellents on your clothes, note that many of the ones we have tested can damage leather and vinyl, and some of them stain synthetic fabrics.