It’s important to protect yourself, as mosquitoes and ticks can transmit debilitating diseases like West Nile virus and Lyme disease. Yet not all repellents are created equal, and some don’t work at all. The repellent you might want to use depends on where you live, how long you’ll be outdoors, and which bugs you’re trying to repel. It also comes down to personal preferences, like fragrance strength.

Mosquitoes are attracted to the “bouquet” of scents on your skin, according to Conor McMeniman, an entomologist and infectious disease expert at Johns Hopkins University.

(What scents are mosquitos drawn to?)

These are chemicals our bodies produce as they break down sugars and proteins for energy, like lactic acid and carbon dioxide, as well as those produced by bacteria on the skin. Some people smell more tantalizing to mosquitoes based on their unique cocktail of chemicals. Scientists believe that repellents disrupt mosquitoes’ and ticks’ ability to smell us.

Here’s what works

The EPA keeps a handy list of compounds that effectively fight off disease-harboring pests, and tells you which pests each repellent keeps away. These repellents have a relatively low environmental toxicity and are safe for humans in accepted doses.

PICARIDIN. Many experts consider picaridin to work just as well as DEET, and it may even last a bit longer. They both offer protection against a slew of irritating insects, including biting flies, gnats, ticks, chiggers, and fleas. Recommended for pregnant women and children.

PERMETHRIN. Outdoorsy types may want to consider using permethrin on their clothes. It’s another EPA-approved repellent that not only masks human scent but also acts as an insecticide, killing insects on contact.
Permethrin is super effective, especially against ticks, and the EPA hasn’t found any evidence that permethrin-treated clothing is toxic to humans or wildlife when used as directed. When applying, avoid getting it on your skin as it can cause irritation. It’s toxic to humans when swallowed, especially for young children. As a pesticide, permethrin is extremely harmful to aquatic organisms and beneficial insects—so you should also be mindful where you spray it and only use it following directions on the label.

Other chemicals may be EPA-certified but less effective. Experts add that products that aren’t sprayed on your person don’t offer much protection.

IR3535 is also a good option if you want something completely odorless. It offers strong protection against mosquitos and other insects, but doesn’t last as long as DEET and picaridin, and it’s a bit harder to find in the U.S.

LEMON EUCALYPTUS. For those that want a completely plant-based option, oil of lemon eucalyptus is the only plant-derived repellent that most experts recommend. Its active ingredient, PMD, is effective against mosquitoes and ticks (although less so than other options), but not chiggers and other biting insects. It also can’t be used in children under three years old, as it can cause skin irritation.
Be wary of other essential oils—”every bottle you buy” can have different contents, are often not tested for safety, can cause skin reactions, and even kill beneficial insects.

Bracelet, clip-on or sticker. Opting for a bracelet, clip-on, or sticker is probably ill-advised, even if the wearable product contains an EPA-approved chemical. No one likes to put DEET on. But these just don’t really work. The reason is that when there’s a strong gust of wind, or even when you walk too fast, the cloud of repellent around the product doesn’t follow, leaving you unprotected.

Pyrethroids, There are some products that heat up and release synthetic pyrethroids, which work in calm weather. But the elements can also render these products useless. These pyrethroids are also harmful to aquatic species, so you shouldn’t use them if you live near a stream or lake.

Zappers and Ultrasonic devises. Multiple experts also agreed that zappers and ultrasonic devices are completely ineffective.

The bottom line, is that you should read the label, do your research about bugs in the area, and make sure to reapply if applicable. The best thing you can do is just be prepared and remember to protect yourself. An ounce of prevention goes a long way.”