What Is Nootkatone Insect Repellent?

Found in grapefruit skin, nootkatone might help keep mosquitos, ticks, and other biting bugs at bay.

The summer months may be full of sunshine and outdoor activities. However, that time also comes with the risk of insects. For the most part, insect bites are harmless and only cause mildly bothersome symptoms, like itching. 

However, some insects, like mosquitos, ticks, and fleas, carry diseases. Insect repellent is one of the best ways to avoid attracting insects. Still, some insects may become resistant to commonly used ingredients in repellent.

In 2020, the Environmental Protection Agency (EPA) approved nootkatone, a natural ingredient found in grapefruit skin and Alaska yellow cedar trees, for insect repellents. As of 2023, nootkatone is not yet commercially available. Still, in the future, the ingredient may help keep insects at bay and reduce the spread of disease.

What Is Nootkatone?

Nootkatone, found in small quantities in grapefruit skin and Alaska yellow cedar trees, can keep biting bugs away for several hours.

In 2020, the EPA approved nootkatone for insecticides and repellents. The Centers for Disease Control and Prevention (CDC) discovered and developed nootkatone, which repels and kills ticks, mosquitos, and other biting bugs.

"According to the CDC, nootkatone kills pests in a unique and different way, which is very important for mosquito control operations," David Brown, a technical advisor to the American Mosquito Control Association, told Health. 

As a food additive, the Food and Drug Administration has classified nootkatone as "generally considered safe." Also, the EPA confirmed to The New York Times that nootkatone is nontoxic to humans and other mammals, birds, fishes, and bees.

How Does Nootkatone Work?

Normally, mosquito control agencies use two pesticides to reduce adult mosquito populations: pyrethroids and organophosphates. 

"These products disrupt the nervous system of the target insect, resulting in mortality," explained Brown. In contrast, nootkatone works differently than pyrethroids and organophosphates. Therefore, nootkatone may work better than products containing other active ingredients that insects may have become resistant to.

Still, it's unclear how nootkatone repels insects. Some experts believe that biting bugs do not like the smell or taste of the chemical. Nootkatone is responsible for the distinctive aroma and taste of grapefruit.

"In some insects tested, areas treated with nootkatone were avoided prior to contact," Karla M. Addesso, PhD, an associate professor in the department of agricultural and environmental sciences at Tennessee State University, told Health. "This suggests that they can smell the nootkatone and that they don't like the smell. Other insects may need to contact the compound in order to detect it, and they may be repelled by the taste."

How To Use Nootkatone Safely

The CDC has partnered with Evolva to develop insect repellents using nootkatone. As of 2023, the EPA is reviewing Evolva's formula to ensure its safety and efficacy.

However, when nootkatone becomes commercially available, people can use the formula on their skin and other items, like clothing, to protect against insects. Like previous insect repellents, you can spray nootkatone directly onto exposed areas. Also, manufacturers may use nootkatone in soaps, sprays, and lotions.

Alternatives to Nootkatone

The Food and Drug Administration has approved nootkatone as an active ingredient in insect repellent. However, the EPA must test and register any manufactured products containing the ingredient separately.

Still, some natural compounds may work the same way nootkatone does when it comes to repelling bugs. For example, Nootka oil and grapefruit oil, available commercially, help repel bugs, noted Addesso. 

"The Nootka oil has a cedar-type smell, and the grapefruit oil is more citrusy due to the other compounds found in the oil," said Addesso. However, placing any pure essential oil directly on the skin is not advisable, as it may cause irritation. 

Instead, "you can place drops of oil on clothing directly if you are not worried about staining them, such as a hat or gloves you use for gardening," explained Addesso. "You can also dilute the oils in a carrier like coconut oil to make lotions as you would any other essential oil. If you make candles with the oils, you can use them outdoors in place of citronella candles."

For other options, you can refer to the EPA's list of ingredients registered as skin-applied insect repellents, including catnip oil and citronella oil.

"Environmental Protection Agency-registered products have undergone studies to ensure they are safe for use, and they are effective when the label directions are followed," said Brown.

How To Prevent Insect Bites

The fight against insect-borne diseases remains a priority for health officials. According to a report published in 2018 by the CDC, diseases caused by the bites of ticks, mosquitoes, and fleas have tripled in the United States since the mid-2000s.

Those diseases include Lyme disease, anaplasmosis, and Rocky Mountain spotted fever from ticks. Also, mosquito-caused illnesses include West Nile, dengue, Zika, and chikungunya. Additionally, fleas can carry and transmit plague. 

Beyond using insect repellents, you can take precautions against mosquito bites, such as:

  • Wearing long-sleeved shirts and long pants
  • Using permethrin on any exposed items, such as clothing or backpacks
  • Using air conditioning or closing windows and doors to keep mosquitos out of your home
  • Sleeping underneath a mosquito net if you are traveling to an area with disease-carrying mosquitos

Also, to prevent tick bites, take note of the following tips:

  • Keep away from tick-infested areas, like grassy, brushy, or wooded areas.
  • Use permethrin on any exposed items.
  • Check yourself, your pets, your children, and any exposed items for ticks.
  • Shower after being outdoors.

A Quick Review

Nootkatone is a natural ingredient in grapefruit skin and Alaska yellow cedar trees that can help repel insects. As of 2023, nootkatone is not yet commercially available. However, in the future, the ingredient may help decrease the spread of diseases carried by insects, like Lyme disease and malaria.

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12 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. Clarkson TC, Janich AJ, Sanchez-Vargas I, et al. Nootkatone is an effective repellent against Aedes aegypti and Aedes albopictusInsects. 2021;12(5):386. doi:10.3390/insects12050386

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