Insect Repellent Active Ingredients
With an increase in new reports regarding insect-borne diseases such as Zika and Lyme disease, it is important to understand different insect repellent active ingredients and how they work. Insect repellents help keep backyards, picnics, and outdoor adventures distraction-free by fending off mosquitos, ticks, biting flies, and more. Some repellents may also protect against insects that carry vector-borne diseases like West Nile virus, Zika, dengue, or Lyme disease.
Skin-applied personal repellents can use different types of active ingredients, each with different benefits and potential concerns. When comparing repellent ingredients, it’s important to understand what science tells us (and what it doesn’t) about how they work.
Mosquitoes and other biting insects are experts at finding people, using cues like the carbon dioxide we breathe out, our body heat, skin chemistry, and even the bacteria on our skin. Personal repellents work by interfering with that process, but exactly how isn’t fully understood. Scientists believe different active ingredients either mask our scent, scramble the signals insects rely on, or simply make us less appealing. Repellents don’t kill insects; they just help keep them from landing or biting. In practice, this means the insects either don’t find us or lose interest when they get close.
Here’s a look at a few of the most commonly used active ingredients in personal repellents.
Comparing Personal Repellent Active Ingredients
Different personal repellent active ingredients work in different ways, each with pros, limits, and considerations. Here’s a side-by-side look at five commonly used active ingredients.| INGREDIENT | WHAT IT IS | PERFORMANCE / EFFICACY | REGULATIONS / SCIENCE | KNOWN CONCERNS |
|---|---|---|---|---|
| DEET | Synthetic repellent developed in the 1940s for the U.S. Army. Has been in market for over 60 years. Widely considered the “gold standard” for mosquito and tick repellents. | Highly effective against mosquitoes, ticks, biting flies, chiggers, gnats, and more. Works for several hours depending on concentration. Effective in high-risk, vector-borne disease regions. | Extensively studied. Registered with the U.S. Environmental Protection Agency (EPA) and under EU Biocidal Products Regulation (BPR). Recognized by the U.S Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) as effective when used as directed. | Possible skin irritation. Animal studies have indicated potential neurotoxicity when large amounts were swallowed, although this type of exposure is not applicable to personal repellent products when used as directed. Can damage plastics or fabrics. Harmful to aquatic life. |
| Picaridin (KBR) | Lab-made version of a compound in the piperidine family. Can be derived from black pepper plants or made synthetically. Used worldwide for over 20 years. | Protects against mosquitoes, ticks, biting flies, gnats, and sandflies. Works for several hours depending on concentration. Often preferred for its lighter feel, without a strong odor or potential to damage to plastics, clothing, or gear. | Registered with the EPA and under BPR. Recognized by the CDC and WHO as an effective option when used as directed. | Mild skin or eye irritation possible. Animal studies have indicated potential liver and kidney effects, although these studies are not clearly shown to be relevant in humans. Harmful to aquatic life. |
| IR3535 | Synthetic repellent developed and marketed in Europe since the 1970s. Registered with the EPA in 1999. | Effective against mosquitoes, ticks, lice, and some biting flies. May require more frequent reapplication than DEET or Picaridin in heavy bug areas. Gentle feel and little odor. | Registered with the EPA and under BPR. Long history of use in the marketplace with no substantial adverse effects. Recognized by the CDC for strong mosquito protection. | Mild eye irritation possible. Can damage some plastics or fabrics. |
| PMD (p-Menthane-3,8-diol) | Botanically inspired active that is chemically processed from oil of lemon eucalyptus or from pine oil extract. In widespread use since 2005. | Protects against mosquitoes and some ticks. Usually lasts a few hours. Reapplication may be needed sooner in hot, humid conditions. | Registered with the EPA and under BPR. It is recognized by the CDC as an effective mosquito repellent. | Eye irritation possible. Strong botanical scent may be unappealing to some. Harmful to aquatic life. |
| Essential Oils (e.g.,geranium, clove, cornmint) | Concentrated plant oils with scents insects tend to avoid. | Shows lower repellency and shorter duration than repellents with DEET, Picaridin, and IR3535. Requires frequent reapplication. | Essential oils used for repellents in the EU require registration. In the US, essential oils meeting certain criteria are exempt from EPA registration, prohibiting these repellents from making claims of protecting against vector-borne disease like West Nile virus, Zika, dengue, or Lyme disease. | Can cause eye and skin irritation or allergic reactions. Potential for photosensitivity. Data on long-term safety is limited vs registered actives. Some have been shown to impact the reproductive system in animal studies. May be harmful to aquatic life. |
For further information
US EPA Pesticide Information
;
CDC Mosquito Prevention
;
EU Biocidal Product Regulations
References to public or governmental organizations -- including the U.S. Environmental Protection Agency (EPA), the Centers for Disease Control (CDC), or the World Health Organization (WHO) -- are provided solely for informational purposes. These agencies do not endorse or recommend any specific company, manufacturer, brand, or product.
Learn more about specific personal repellent active ingredient below.
DEET is a common and effective insect repellent active ingredient that can help reduce the chance of insect bites from species that may carry diseases like West Nile virus, Zika, dengue, or Lyme disease.
DEET has been used in personal repellents for decades and was first developed by the U.S. Department of Agriculture for the Army about 80 years ago. It’s considered an effective active ingredient against a wide variety of biting insects, including mosquitoes, ticks, biting flies, chiggers and gnats. Public health agencies such as the U.S. Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) include DEET among the options recognized for personal protection. It is also registered with the U.S. Environmental Protection Agency (EPA) and under the EU Biocidal Products Regulation (BPR).
DEET has been extensively studied by regulatory agencies, academic institutions, and private industry. Its proven efficacy, ability to provide protection for a long period, and extensive research make it the benchmark against which newer repellent ingredients are measured.
DEET doesn’t kill insects but protects against them by deterring them from landing on your skin or clothes.
How does DEET work?
Exactly how repellents work isn’t fully understood. Scientists believe DEET works to mask our scent or confuse and interfere with mosquito receptors that detect body heat, carbon dioxide and skin chemicals – all the cues that make us attractive. This means DEET makes it difficult for insects to recognize us as a source of food. Mosquitoes may still land but are less likely to bite.
Are there concerns associated with DEET?
Most people use DEET without problems, though some may experience mild skin irritation or, rarely, allergic reactions. It has been extensively studied for potential health effects, including neurological, cardiovascular, developmental, reproductive and endocrine disrupting effects. Serious effects seen in animal studies, like neurotoxicity, have occurred where large amounts were swallowed, though this type of exposure would not be applicable for skin repellents when used as directed.
Regulatory agencies, including the U.S. Environmental Protection Agency (EPA), have reviewed the science and found no credible evidence that DEET causes reproductive, developmental, or hormone-related issues when used as directed. The EPA also concluded that scientific evidence does not indicate DEET is an endocrine disruptor.
From an environmental perspective, DEET can harm aquatic life and has been detected in water sources, but it is not known to persist in the environment. DEET may damage certain plastics, coatings, and fabrics, so care should be taken when using it near these materials.
Reference: National Pesticide Information Center DEET Fact Sheet