There's nothing worse than an undesirable bug bite. While flea and tick repellents can help with that and are safe and effective when used as directed, many people don't feel comfortable using them on their skin, clothing or in the yard. Not only do many of them include ingredients we can't even pronounce, they don't exactly smell awesome.
Thankfully, scientists and herbalists have developed all-natural methods to keep these critters away and reduce your chemical exposure.
"Plants are beneficial to us in so many ways that we are unaware of," says Michelle Ornstein, certified aromatherapist, natural skin care formulator and president of Enessa Organic Skin Care. According to Ornstein, it's our responsibility to look to nature whenever we can instead of relying on manufactured chemicals. "Not only can they help to balance, clarify and hydrate the skin, but since plants develop their own defense mechanisms, they can actually repel certain insects when applied topically."
Before you start dousing yourself in oils, a note of caution: While some of the botanical oils are suitable for direct skin contact, others work best sprayed on clothing or under rugs and cushions.
How Essential Oils Work in Repelling Insects
Plants produce natural compounds (known as secondary metabolites) that are thought to play a role in protecting the plant from parasites and predators, including insects, according to a June 2018 review published in Genes. Essential oils are one product of the secondary metabolism process. "This gives a logic to the use of essential oils as insect repellents and would explain why they are such effective insect repellents," says Jimm Harrison, holistic health and essential oils expert and author of Everyday Healing with Essential Oils.
Understanding how essential oils impact insects requires a deep dive into science, biology and physiology adds Harrison, but in a nutshell, the "how" is best understood through the ability of the plant to protect itself from predators.
Effectiveness of Essential Oils in Repelling Insects
While essential oils have been deemed safe to use by the Environmental Protection Agency (EPA), that doesn't attest to their effectiveness. An October 2018 review of studies published in Biomed Research International found that essential oils fail to last as long or provide as strong protection against insects as chemicals like diethyltoluamide (DEET).
Integrative health expert Taz Bhatia, MD, author of Super Woman RX, maintains that they can be effective for mild insect exposure, but not as much so against tick-borne disease, Zika and other pathogenic insects. "If you are going to regions with these insects, I would add picaridin (an insect repellent) and use additional precautions like covering your arms and legs and wearing hats," she adds.
Dr. Bhatia also suggests reapplying frequently as they tend to evaporate. When this happens, their effectiveness dwindles. Instead of using a single oil, Harrison finds that using a combination of essential oils is the most effective method of keeping insects at bay.
Safety and Essential Oils
Essential oils, which are obtained from steam distillation, are highly concentrated and must be diluted with carrier oils — such as Neem or Tamanu oil — when applied to the skin directly, warns Ornstein. These carrier oils have repellent properties as well.
Keep in mind that some essential oils can be harmful — even toxic — especially when consumed orally or applied directly to the skin without a carrier. Dr. Bhatia cautions that they should only be used topically and never orally.
Harrison points out that lemon-scented oils do have potential for sensitivity in some individuals. Also, some oils, such as bergamot and grapefruit, are photosensitive. This means that if you apply them to your skin, it's important that you stay out of the sun.
Essential Oils That Naturally Repel Insects
EPA-registered active ingredient 2-undecanone, an essential oil derived from the leaves and stems of the wild tomato plant is effective at repelling ticks — including the blacklegged and lone star tick, according to the Centers for Disease Control and Prevention (CDC). It can be used on skin, clothing or your outdoor gear and is commercially available.
Garlic may not smell as great as some of the other essential oils on the market, but the CDC maintains that it is an effective method for repelling blacklegged ticks when it comes to lawns and gardens.
3. Lemon Eucalyptus
Dr. Bhatia is a fan of lemon eucalyptus oil for keeping bugs at bay. "It contains citronella and the terpenes limonene and eucalyptol," she explains, pointing to a January 2019 study published in Environmental Science and Pollution Research which shows that terpenes (organic compounds produced by plants) are very effective insect repellents.
While the CDC agrees that eucalyptus is an effective mosquito repellent ingredient, they do not recommend using lemon eucalyptus in essential oil form as a repellent. This is because it hasn't undergone similar, validated testing for safety and efficacy, and it's not registered with EPA as an insect repellent.
Lavender may smell great, but is it efficient at keeping bugs away? While there isn't a whole lot of evidence that lavender oil is an effective insect repellent, one August 2017 study published in the journal Ticks and Tick-born Diseases found it to be one of 11 essential oils to be relatively successful in repelling dermacentor reticulatus ticks. Dr. Bhatia points out that its anti-inflammatory properties give it insect-repellent power.
While lavender is considered one of the safest essential oils, it is not recommended for use during the first 20 weeks of pregnancy or if you're planning to become pregnant, because its effects have not been widely studied. When applied topically, lavender may irritate the skin.
According to Dr. Bhatia, lemongrass contains the compound cymbopogon nardus, which repels mosquitoes. A March 2013 study in the Journal of Essential Oil Bearing Plants found that essential oils containing the compound were effective in repelling the insects, however, did not work as well as DEET.
Citronella is part of the same family as lemongrass, which accounts for the citrusy scent many of us have come to associate with summer. You likely recognize the smell from many commercial bug sprays and candles. "Citronella contains terpenes which repel insects," says Dr. Bhatia.
For many years, citronella candles were thought to be an effective tool to keep mosquitoes at bay. However, while a July 2018 review published in Current Drug Discovery Technologies found that the fragrant oil has some merit as a bug repellent in oil form (though less effective than DEET). When it comes to candles, a January 2017 study published in the Journal of Insect Science warns that citronella's effectiveness as a repellent is minimal.
7. Juniper Berry
An April 2016 study in the journal Molecules found that juniper berry (juniperus formosana) was toxic to two insects: The red flour beetle and booklouse, leading scientists to conclude it could be an effective insect repellent.
Harrison points to scientific evidence that Nootka (an Alaskan yellow cypress tree) and grapefruit contain a compound called nootkatone, which is effective in battling bugs. According to the CDC, nootkatone — which can be formulated for use in soaps, sprays and lotions — works as a repellent and insecticide for use against ticks (for example, the blacklegged tick) and Aedes mosquitoes — the bloodsuckers that spread Zika and other viruses.
- Ticks and Tick Borne Diseases: “The Repellent Efficary of Eleven Esstential Oils Against Adult Dermacentor reticulatus ticks”
- Centers for Disease Control and Prevention: “Natural Tick Repellents and Pesticides”
- Research Gate, “The Potential of Secondary Metabolites in Plant Material as Deterents Against Insect Pests: A Review”
- Biomed Research International: "Essential Oils as Repellents Against Anthropods"
- Environmental Science and Pollution Research: "Insecticidal Potential and Repellent and Biochemical Effects of Phenylpropenes and Monoterpenes on the Red Flour Beetle, Tribolium Castaneum Herbst"
- Journal of Essential Oil Bearing Plants: "Mosquito Repellent Actions of the Essential Oils of Cymbopogon citratus, Cymbopogon nardus and Eucalyptus citriodora: Evaluation and Formulation Studies"
- Current Drug Discovery Technologies: "Therapeutic potential of Citronella Essential Oil: a review"
- Journal of Insect Science: "Efficacy of Some Wearable Devices Compared with Spray-On Insect Repellents for the Yellow Fever Mosquito, Aedes aegypti (L.) (Diptera: Culicidae)"
- Molecules: "Contact and Repellent Activities of the Essential Oil from Juniperus formosana against Two Stored Product Insects"
- Centers for Disease Control and Prevention: "Nootkatone for Insecticide and Repellent Development"