Dealing with pesky bug bites is already among the worst parts of warm weather, but the incessant scratching isn’t the only nuisance. State health departments report approximately 30,000 cases annually of Lyme disease—spread by deer ticks—to the CDC across all 50 states, and this year, the tick threat level is above average in four regions (Northeast, Midwest, Southeast, and Southwest). Further, in 2018 the CDC reported 2,544 cases of mosquito-borne West Nile Virus across the country, with the highest concentration in the Midwest.
Mitigating the risks that insects like ticks and mosquitoes pose to humans starts with preventing the bites in the first place. Wearing loose-fitting clothing that covers your limbs when you spend time outdoors can keep bugs from piercing your skin, but may not be your top wardrobe choice in the summer heat. Bug spray—or topical insect repellent—and pesticide-treated clothing make you an unappealing snack. And, thanks to science, there are many options to choose from.
How to use insect repellents
Most repellents instruct you to evenly spray six to eight inches away over all exposed skin for a proper coating. With any topical insect repellent, avoid spraying near the eyes and mouth or any cuts and wounds to avoid accidental irritation or ingestion. To apply the product to the rest of the face, spray it on hands first (and wash them afterward). When protecting children, avoid their hands (so they’re less likely to get it in their eyes or mouth), and don’t apply it to infants younger than two months old. If you’re spending time in areas known to have ticks, be sure to check yourself and your kids from head to toe once you’re indoors. Your repellent should then be washed off, mainly because its effects are no longer needed when there are no bugs around.
How they fend off bugs
All insect repellents work in relatively the same way, but scientists are not positive on the exact mechanism; they’re even unsure of how DEET, the oldest and most researched skin repellent, does its job. “SC Johnson states in their materials that the science of how [DEET] works continues to evolve,” says Tom Skinner, the public affairs officer at the CDC. Researchers believe these substances repel in one of two ways: by jamming the odor receptors of insects, which results in them being unable to find and land on a host, or by making the treated skin they land upon simply taste bad, so they move on.
Another mechanism for repelling bugs is by poisoning them with an insecticide. Permethrin, which is applied to clothing rather than directly to skin, affects the nervous system of insects that land on treated fabric, ultimately causing muscle spasms, paralysis, and death.
Below, a primer of active ingredients you can trust—and the ones you should skip.
What it is: Bug sprays containing DEET have long been the gold standard since it was developed in 1946 for the US Army and first sold to consumers in 1957—and for good reason. “DEET is the most well studied and single most effective ingredient to prevent bites from a variety of different insects,” says Dr. Joshua Zeichner, a board-certified dermatologist based in New York City.
What it repels: Products containing 30 percent DEET protect against biting insects, including mosquitoes, ticks, and flies for up to eight hours, per Consumer Reports’ tests. The CDC reports you will see repellents that range from 4 to 100 percent DEET on the shelves, with greater concentrations potentially working for a longer period of time (up to 12 hours for some higher-percentage DEET products)—but with the same efficacy—than lower ones.
Safety track record: Its potential toxicity (or lack thereof) has been well studied, and DEET is safe for human use when used appropriately. You should avoid applying DEET under clothing—it’s unnecessary and can cause possible skin irritation from overexposure to the chemical.
Good to know: The EPA says DEET can be used “without posing unreasonable risks to human health or the environment,” but while DEET is considered safe and effective, some people stray from the chemical because of its strong scent and greasy feel on the skin. It’s also known to damage plastic and synthetic-fabric gear, such as jackets and tents.
Popular products that contain DEET include:
Off! Deep Woods Insect Repellent ($10.16 on Amazon)
3M Ultrathon Insect Repellent Lotion ($6 on Amazon)
Repel 100 Insect Repellent ($7.47 on Amazon)
Ben’s 100% DEET ($10.59 on Amazon)
What it is: Picaridin is a synthetic chemical that mimics a natural chemical found in the black pepper plant. It has been used as an insect repellent in the US for about 14 years.
What it repels: Picaridin is just as effective as DEET when used in a concentration of 20 percent, repelling mosquitoes, ticks, fleas, some flies, and chiggers for up to 12 hours and flies for up to eight hours, according to Consumer Reports.
Safety track record: Picaridin was developed in the 1980s and used in Europe and Australia before its US introduction in 2005. The chemical has a low toxicity level and poses no threat to the environment.
Good to know: In contrast to DEET, picaridin has a minimal odor and will not damage synthetic materials. To date, no studies have uncovered any safety issues with picaridin, but this chemical has also been in the spotlight less time than DEET and therefore has been far less scrutinized.
Popular products that contain picaridin include:
Sawyer Products Premium Insect Repellent with 20% Picaridin ($8.95 on Amazon)
Avon SSS Bug Guard Plus Picaridin Pump Spray ($17.75 on Amazon)
Ranger Ready Repellents Picaridin 20% Tick + Insect Repellent Spray ($10.99 on Amazon)
Natrapel 12-Hour Mosquito, Tick and Insect Repellent ($4.99 on Amazon)
Try: Oil of lemon eucalyptus
What it is: Oil of lemon eucalyptus (OLE), also known as para-menthane-diol (PMD), is a synthesized plant oil, first introduced as an insect repellent in 2000.
What it repels: OLE repels against mosquitoes, biting flies, and gnats for up to six hours when it’s used in a higher concentration (about 30 percent) in a product. Its efficacy against ticks is unproven.
Safety track record: OLE does not pose a health risk to humans or the environment, however, the CDC warns against using OLE on children under the age of three due to a lack of testing on that age group.
Good to know: Oil of lemon eucalyptus is often referred to as lemon eucalyptus oil, but the two are actually different. OLE is modified from the plant oil to increase the naturally occurring insect-repelling properties. For this reason, OLE is EPA-registered as an effective insect repellent, whereas lemon eucalyptus oil is not.
Popular products that contain OLE include:
Repel Plant-Based Lemon Eucalyptus Insect Repellent ($5.29 on Amazon)
Murphy's Naturals Lemon Eucalyptus Oil Insect Repellent ($23.95 on Amazon)
Cutter Lemon Eucalyptus Insect Repellent (Starting at $9.57 on Amazon)
Coleman DEET Free Lemon Eucalyptus, Naturally-based Insect Repellent ($9.76 on Amazon)
What it is: IR3535, a synthetic version of a plant-based amino acid, was introduced in bug sprays in Europe about 20 years ago, and brought to the US market in 1999.
What it repels: IR3535, often found in concentrations of 10 to 20 percent, is an effective repellent against mosquitoes, deer ticks, body lice, and biting flies and works for approximately four to eight hours.
Safety track record: It has been used as a repellent in Europe for two decades and the EPA reports there has been no substantial adverse effects to humans or the environment.
Good to know: Like DEET, IR3535’s manufacturer, Merck Group, says it can cause damage and break down synthetic fabrics, so read clothing labels before spraying it.
Popular products that contain IR3535 include:
R&R Lotion Insect Repellent Lotion Deet Free ($12.32 on Amazon)
Coleman SkinSmart DEET-Free Spray Insect Repellent (IR3535) (Starting at $6.99 on Amazon)
Skip: essential plant oils
What they are: Those looking for natural option to repel bugs suggest using essential oils such as lemongrass, lemon eucalyptus, citronella, or peppermint. These are derived from plants.
What they repel: A number of products that contain these oils claim to repel mosquitoes (but typically no other insects) with frequent application. But as they are not required to be registered with the EPA, the government does not track efficacy studies. However, Consumer Reports found them to be largely ineffective.
Safety track record: These oils are not registered with the EPA for use as insect repellents, and thus their safety data is uncollected.
Good to know: To use these, you would typically apply a carrier oil, an oil used to dilute essential oils, and rub into the skin. Some companies sell premixed formulas as well.
Another worthy option: Permethrin
What it is: An alternative to applying repellent on the skin is wearing clothing that repels. Permethrin is an insecticide that outdoor gear manufacturers impregnate into fabric or you can buy in spray form to make your clothing a bug death trap.
Safety track record: Permethrin was first registered with the EPA in 1979. Despite the chemical having environmental risks, such as being toxic to freshwater organisms, the EPA says that the benefits outweigh the negatives.
Good to know: The protection won’t last forever: depending on the brand, clothing treated with permethrin can be effective for up to 70 washes. The DIY sprays will last about six washes before you need to reapply (which you can do with any previous permethrin-treated clothing).
Popular products that contain permethrin include:
Sawyer Products Premium Permethrin Clothing Insect Repellent ($14.99 on Amazon)
Repel Permethrin Clothing & Gear Insect Repellent ($15.25 on Amazon)
Ben’s Clothing and Gear Insect Repellent ($17.99 on Amazon)
Prices are accurate at the time this article was published, but may change over time.