Best Insect Repellents

A comprehensive guide to insect repellents, effectiveness and safety. DEET vs Picaridin vs Permethrin vs Oil of Lemon Eucalyptus.

by Kelly Hodgkins
May 23, 2018

There is a lot of confusion surrounding insect repellent options for backcountry travel. Which backwoods bugs do I need to target? How effective are existing solutions? Are natural solutions better than synthetic formulas? We are here to help you separate the fact from fiction so you can keep the bugs at bay when you go outside to play.


There are many different bug sprays on the market, but not all of them work the same.

DEET: By far, the most effective when used in high concentrations.

It is the gold standard to which all other repellents are compared. Most commercially available DEET is sold in concentrations ranging from 10% (about 2 hours of protection) up to 100% (up to 10 hours). Some versions feature a time-release formula that can provide up to 12 hours of protection.

It is widely used in repellents against biting insects like black flies, mosquitoes, and ticks. It is sold as either a spray, a lotion or in wipes that you apply to your skin or clothing. Be careful when you apply it as DEET is a plasticizer and can damage rubber, plastic, leather, vinyl, rayon, spandex, or elastic. DEET will come off when you sweat, so you should plan to reapply as needed or use a sweat-resistant lotion. Some people also find it to be greasy when applied to the skin.

PICARIDIN: Equally as effective as DEET when used at lower concentrations (20%)...  and lacks some of DEET's unpleasant side effects.

Picaridin is a DEET alternative that was developed in Europe in the 1980s and made available in the US in 2005. It is odorless, non-greasy and doesn't damage gear or clothing. It is available in concentrations between 7% and 20% which provides about 5 hours of protection. It is sold as either a spray, a lotion or in wipes.

PERMETHRIN: Effective on materials (not your skin) that kills (not repels) ticks, mosquitoes and other arthropods.

This insecticide is typically sprayed on gear and clothing because it is odorless and won't cause any stains. Once treated, Permethrin can last for up to 6 washings. Clothing that is purchased with a Permethrin can be washed 70 times before it needs to be re-treated. Permethrin is typically not used on the skin because there are no benefits to applying it topically.

OIL OF LEMON EUCALYPTUS Moderately effective. But widely considered to be more safe.

On the botanical side, the best plant-derived formulas provide about 3-5 hours of protection, the equivalent of a low dosage of DEET. Oil of Lemon Eucalyptus, a chemically synthesized or refined version of lemon eucalyptus oil, is the most effective plant-based formula. Other natural bug sprays include essential oils such as lemongrass, citronella, peppermint, geraniol, soybean, and rosemary. These products don't last as long as Oil of Lemon Eucalyptus providing less than an hour of protection. These oils are available as sprays or lotions. You can even buy them separately and make your own custom repellent mix.


insect repellent spray

DEET: Questionable.

DEET's safety record has been questioned, but studies have shown that it is safe to apply at commercially available concentrations (10% - 100%) when used as directed. Most problems with DEET arise from overuse or from ingesting the chemical. DEET is registered by the EPA as a biopesticide and has been studied extensively since its development in 1946.

Adults can use any concentration of DEET, while children should use concentrations of 30% or less. You should not use repellents on infants younger than two months. If you are concerned about DEET, then apply it only when needed and use lower dosages under 30%. A higher concentration DEET is no more effective than a lower one. It only lasts longer. You also can apply the repellent to clothing and not your skin.

PICARIDIN: Undetermined.

Available in the US only since 2005, Picaridin is a relative newcomer to the repellent market. Though it is regulated by the FDA, it doesn't have the decades of research and usage behind it like DEET. Existing studies show that Picaridin is safe to use, but not enough time has passed for any long-term health effects to show up. 

PERMETHRIN: Generally considered safe.

As long as you follow the manufacturer's instructions and don't ingest it. See full Permethrin Spray Safety Guide.


Also known as "OLE", it is unique among the botanicals. It is the only plant-based bug spray classified by the government as a 'biopesticide". It contains a chemical, PMD, that has been shown to be an effective repellent. The repellent can be refined from lemon eucalyptus oil to contain up to 70 % PMD or synthesized chemically and sold commercially as PMD. Be careful not to confuse the PMD-rich Oil of Lemon Eucalyptus with lemon eucalyptus essential oil, which is low in PMD and not nearly as effective against bugs.

The essential oils (lemongrass, citronella, peppermint, geraniol, soybean, and rosemary) are not regulated by the EPA because their use does not pose any serious health risk. They are safe to use, so the EPA doesn't bother to test them to see how well they work.

How Repellents Work

STEP 1) Insect Smells You: Insects like black flies and mosquitoes have no problem finding their victims. They use their keen sense of smell to detect an unsuspecting host from up to 50 meters away. These blood-sucking bugs are attracted to carbon dioxide which is exhaled when you breathe. Movement, lactic acid in sweat and heat also are attractants, a combination that makes hard-working hikers a tasty treat.

STEP 2) Repellents Block It's Odor Receptors: As their name implies, most repellents don't kill their target insects. Instead, they work by repelling the insects, so they don't even come near you. The most effective bug sprays target the insect themselves. Synthetic repellents like DEET or Picaridin work by blocking neurons and the odor receptors on a mosquito's antennae and mouth-parts. These receptors can detect chemicals on your skin and the carbon dioxide you breathe. When the insect's receptors are blocked by a repellent, they can't smell you, so they can't find you and bite you.

*The one exception is permethrin which is an insecticide and not an actual repellent. Permethrin is a synthetic version of the natural insecticide Pyrethrin, which is found in the Chrysanthemum flower. Permethrin kills insects like ticks and flies on contact. When used with a repellent like DEET, permethrin provides up to 99.9% protection from mosquitoes and ticks.

Danger of Common Insect Bites

insect bites mosquito black fly tick

Before you even pick up a can of insect repellent, you need to think about the insects you are trying to repel and whether you actually need a chemical repellent to deal with them. Some insects carry diseases that can harm you, while others are just a nuisance that make your trip uncomfortable. Mosquitoes and ticks are by far the two most common insects you will encounter on the trail and the two most pressing to deal with.

MOSQUITOES: West Nile Virus and encephalitis in USA; Malaria and Dengue fever in tropical regions.

In tropical areas carry a wide range of disease including malaria, Dengue fever, and other serious illnesses. You need to be aware of these diseases when traveling internationally, but they are not a significant concern if you a staying within the US.

In the United States, mosquitoes carry fewer diseases - but that doesn't mean we can be complacent about them. Mosquitoes can transmit West Nile virus and encephalitis. West Nile virus is one of the most common mosquito-borne diseases and produces a flu-like illness in most people. There were 2,002 reports cases of West Nile Virus last year in the US. Encephalitis, which is an inflammation of the brain, is a much more severe disease. It causes flu-like conditions and in rare cases, brain damage and death. Thankfully, it is relatively obscure with only a handful of cases reported each year.

TICKS: Lyme disease and rare fevers.

Probably the most challenging pests that you'll encounter on the trail. They are small, sometimes too small to see, and can bite you without you noticing. There are about a dozen different ticks in the US, but only a few spread disease. The diseases they do carry range from mild flu-like symptoms to severe infections that lead to hospitalizations and long-term antibiotic treatment.

The most common ticks encountered on the trail are the deer or blacklegged tick and the dog or wood tick. Though the dog tick can transmit Rocky Mountain Spotted Fever, it is very rare. It's the deer tick that is responsible for the majority of reported tick-borne illnesses.

Lyme disease is the most well-known disease you can get from a tick and one of the most serious. If you contract Lyme disease, you can expect a two- or three-week course of antibiotics. Don't mess around with ticks and Lyme. If left untreated, Lyme disease could lead to life-long complications that affect your quality of life.

BLACK FLIES: No diseases in USA; onchocerciasis and mansonellosis in tropical regions.

A great example of an insect that doesn't really require a repellent. These tiny biting flies are a nuisance, but they don't commonly carry disease. In the spring when the air gets thick with these biting flies, your best strategy is to cover your exposed skin with clothing and bug netting, hike quickly through the swarms and get to a higher elevation where they are present in much lower numbers. Thankfully, the black fly season is short and not something hikers have to contend with for the whole season.

Synthetic vs Natural Ingredients

permethrin vs lemon eucalyptus

(Permethrin Chemical and Lemon Eucalyptus)

There are two broad categories of repellents - synthetic compounds that are man-made and natural repellents that are derived from plants and plant extracts.

SYNTHETIC: The most popular synthetic repellent is N,N-diethyl-m-toluamide, otherwise, known as DEET. An estimated one-third of the US population uses DEET each year. The repellent Picaridin and the insecticide permethrin also are synthetic compounds used as an alternative to DEET.

NATURAL: Natural formulas work just like chemical counterparts and in some cases are equally as effective at lower concentrations. Most of these natural formulas are "essential oils" or other plant-based extracts and are considered to be kinder and gentler than their chemical counterparts. They don't stain clothing or ruin gear like chemical repellents. Even though they may be natural, it doesn't mean they are without problems. Just like synthetic formulas, you need to be careful when applying natural solutions to your skin as they could cause a rash, especially if you have sensitive skin.

Best Insect Repellents

bug insect repellent deet


Type: Chemical repellent

EPA Registered: Yes

Duration: 8 hours at 30%

The synthetic compound N,N-diethyl-m-toluamide (DEET) is the gold standard to which all other bug sprays are compared. DEET was developed in the 1940's for the US Army during World War II and was first used publicly in the 1950s. An estimated 78 million people in the US, and 200 million people globally use DEET each year. DEET is widely used in repellents against biting insects like black flies, mosquitoes, and ticks. It is known for its longevity. Most common DEET formulas of 20% provide up to 5 hours of protection. Higher concentrations and time-release formulas can protect you for up to 12 hours. DEET has its drawbacks, though. The chemical can be caustic; irritating skin and causing damage to any gear containing rubber, plastic, leather, vinyl, rayon, spandex, or elastic.


bug insect repellent picaridin


Type: Chemical repellent

EPA Registered: Yes

Duration: 8 hours at 20% concentration

Picaridin was developed in Europe as an alternative to DEET in the 1980s. It was chemically synthesized to mimic the natural compound piperine, which is found in the plants used to make black pepper. It is colorless, odorless, doesn't irritate skin and won't damage gear or clothing. When used at a 20% concentration, Picaridin is as effective as DEET at repelling insects. 


bug insect repellent permethrin


Type: Chemical Insecticide

EPA Registered: Yes

Duration: 8 hours at 20% concentration

Permethrin was first discovered in 1973 and is on the World Health Organization's Essential Medicine list for its use in treating scabies and lice. Now backpackers are using the compound as a first line defense against mosquitoes, black flies and ticks. You can read more about Permethrin in our recent overview


bug insect repellent oil of lemon eucalyptus OLE


Type: Refined from Lemon Eucalyptus Oil or Synthesized chemically

EPA Registered: Yes

Duration: 2-3 hours at 30% concentration

Oil of Lemon Eucalyptus is a concentrated version of lemon eucalyptus oil, which is extracted from the leaves and twigs of the lemon-scented gum eucalyptus plant, Eucalyptus citriodora. PMD is the active ingredient in Oil of Lemon Eucalyptus and equally as effective as DEET. It doesn't last as long as DEET, but it is much less caustic. Its biggest drawback is its smell -- forget to close the bottle, and the strong smell of OLE will permeate everything in your pack.

Be careful when shopping for Oil of Lemon Eucalyptus products. Some bug sprays contain lemon eucalyptus oil which is an essential oil extract that contains small amounts of the active ingredient PMD. Oil of Lemon Eucalyptus is concentrated version of this essential oil and contains up to 70% PMD. Some bug sprays also use PMD that has been chemically made from synthetic citronellal.


bug insect repellent citronella oil


Type: Plant Oil

EPA Registered: No

Duration: 30 minutes

Citronella or lemongrass oil is derived from the Cymbopogon citratus plant. The resulting oil is effective against mosquitoes and flies, but its limited lifespan reduces its effectiveness. It is mot commonly packaged into candles that are burned as a backyard repellent. It also can be used topically as an oil or as a strong citrusy smell that is very distinctive.


bug insect repellent soybean blocker organic spray


Type: Plant Oil

EPA Registered: No

Duration: 1.5 hours at 2% concentration

Among the plant oils, soybean oil is one of the most effective bug sprays. It doesn't compare to DEET, but its does provide protection in small doses. Add it to lemongrass and you'll have a great homemade repellent mixture. You also can grab a bottle of Bite Blocker for Kids which has 2% soybean oil as its active ingredient.


bug insect repellent catnip spray


Type: Plant Oil

EPA Registered: No

Duration: 30 minutes

Catnip is known for its ability to drive cats wild, but it also works as an insect repellent. Catnip contains nepetalactone, which gives the plant its characteristic odor and is responsible for warding off insects.


bug insect repellent geranium oil cinnamon oil lavender tea tree oil


There are several common essential oils that are used in bug sprays including geranium oil, cinnamon oil, lavender, and tea tree oil. When combined, these alternative oils have been shown to ward off insects for 30 minutes or less, making them useful for short adventures that don't require the heavy-duty protection of DEET, Picaridin or OLE.

If you prefer not to use a topical repellent but still want protection from insects, then you are out of luck. Most alternatives, like sound emitting bracelets or garlic capsules, have not been found to be effective against insects. Even repellent-infused bracelets have limited usage as most bug sprays are effective only over a small distance. A repellent on your wrist won't help your exposed calves.

DIY bug insect repellent


If you are looking to make your own insect repellent, you'll have to visit your local essential oils supplier to get your components. Once your essential oil cupboard is stocked, making your a homemade repellent is simple. Add the following ingredients to a 2-ounce spray bottle, shake to mix and apply as needed. Make sure to shake each time before using and store in a cool, dark place.

*Recipe 1: 1 teaspoon sweet almond oil (carrier oil), 12 drops lemongrass, 6 drops eucalyptus, 2 drops citronella

*Recipe 2: 6 ounces witch hazel, 2 ounces castor oil, 5 drops cinnamon oil, 15 drops eucalyptus oil, 15 drops citronella oil

Final Tips

Avoiding ticks and mosquitoes by staying inside is one way to eliminate your exposure to these diseases, but that's not an option for someone who loves to go outside. You can't avoid ticks, mosquitoes and other pests when hiking, but you can take steps to minimize your risk.

1. Use a physical barrier. Like clothing and bug netting to prevent being bitten. Understandably, these can be cumbersome- who wants to wear long pants and shirts in the heat of summer? Most people instead opt to use a chemical repellent that will keep the insects away and won't cramp your style. 

2. Mosquitoes are usually most active at dusk. If you're running low or just hate applying sprays and lotions, waiting until dusk might be an option.

3. Risking disease is just not worth it. It's vital that you consider a repellent before you head out on a long hike. You don't want to return home with a severe illness or, even worse, get sick on the trail. Mosquitoes are annoying, and they carry disease so you will want to protect yourselves from them. There is no debate about repellents when it comes to ticks. The seriousness of these tick-borne diseases is reason enough to use one or even two repellents to keep these bugs at bay.

Kelly Hodgkins photo

About Kelly Hodgkins

By Kelly Hodgkins: Kelly is a full-time backpacking guru. She can be found on New Hampshire and Maine trails, leading group backpacking trips, trail running or alpine skiing.

About Greenbelly

After thru-hiking the Appalachian Trail, Chris Cage created Greenbelly to provide fast, filling and balanced meals to backpackers. Chris also wrote How to Hike the Appalachian Trail.

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