Deet in Repellent: Understanding Its Effectiveness and Safety

Deet is a highly effective ingredient in insect repellents, capable of repelling mosquitoes and ticks for up to 12 hours.

It's worth noting that deet is not a repellent itself, but rather a solvent that helps other active ingredients bind to the skin.

Deet is generally considered safe when used as directed, but it can cause skin irritation and other health issues in some individuals.

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DEET is a yellowish liquid that repels biting insects like mosquitoes, ticks, flies, and fleas when applied to skin or clothing.

It doesn't kill these bugs, but protects against them by keeping them from landing or biting.

Over one-third of the U.S. population uses deet-based products every year to fend off biting bugs, according to the Environmental Protection Agency.

Deet has been available to consumers since 1957, after being discovered by the U.S. military and the Department of Agriculture.

Government scientists tested thousands of chemicals before finding deet as one of a handful of effective mosquito repellents.

Consider reading: Natural Insect Repellent for Bed Bugs

Despite its long history, how deet works is still not fully understood, with theories involving mosquitoes' olfactory system.

Deet may mask or confuse mosquitoes' odor-sensing abilities, or simply register as an odor to be avoided.

In one 2019 study, mosquitoes bred without the ability to detect deet's odor still sensed the chemical through their legs and flew away without biting.

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DEET is effective against a variety of invertebrates, including ticks, flies, mosquitoes, and some parasitic worms. A 2018 systematic review found no consistent performance difference between DEET and icaridin in field studies.

DEET is safe to use on pregnant women in moderation. Studies have shown that while DEET molecules can cross the placenta, they do so in very small concentrations, and babies born to mothers who used DEET were not smaller or sicker.

The key to using DEET-based products safely is to follow product instructions and take basic precautions. Use the right concentration, apply the repellent properly, and know when not to use it.

Here are some safety tips to keep in mind:

DEET is effective against a variety of invertebrates, including ticks, flies, mosquitoes, and some parasitic worms.

A 2018 systematic review found that DEET and icaridin are equally preferred mosquito repellents, with 50% DEET offering longer protection but not being available in some countries.

DEET provides longer protection compared to lower concentrations, but this may not be necessary for everyone.

Concentrations of DEET can range from less than 10% to nearly 100%, but concentrations greater than 50% don't increase the duration of protection.

Higher concentrations of DEET can be safely applied to clothing, although it may damage some types of synthetic fibers.

The National Health Service (NHS) recommends using a concentration of 50% when visiting areas of the world with malaria.

Health Canada decided to limit DEET concentration to 30% in the country from the end of 2004 due to an increased long-term risk observed with repeated applications.

The Centers for Disease Control and Prevention (CDC) recommends 30–50% DEET to prevent the spread of pathogens carried by insects.

Here's a quick rundown of the recommended DEET concentrations for different situations:

The CDC recommends that DEET should not be used on children younger than 2 months of age.

Between the early 1980s and late 1990s, 14 cases of potentially DEET-related encephalopathy (brain damage) were reported in the medical literature, all but one of them in children who were 8 or younger.

Any chemical poses some risk, especially when misused, but experts seem to agree that 14 is a vaningly small number of incidents when compared with the estimated 100 million annual human applications of DEET made during that same time period.

Infants and children actually accounted for a greater proportion of cases with no or moderate effects, while adults accounted for a greater proportion of the cases with moderate and major effects.

As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications.

Fewer than 50 cases of serious toxic effects have been documented in the medical literature since 1960, and many of these cases involved long-term, heavy, frequent, or whole-body application of DEET.

The risk of experiencing any adverse health effects is reduced when products containing DEET are used according to label instructions and concentrated DEET products are avoided.

Individuals who require large exposure to DEET, such as those working in the Everglades, may be more likely to experience adverse effects like insomnia, mood disturbances, and impaired cognitive function.

Health Canada barred the sale of insect repellents for human use that contained more than 30% DEET in a 2002 re-evaluation, citing human health reasons.

If you're looking for alternatives to DEET, there are a few effective options to consider. Picaridin, a repellent modeled after a molecule found in pepper plants, has done well in Consumer Reports' tests and is safe according to the World Health Organization and the CDC.

Oil of lemon eucalyptus (OLE) is another active ingredient that has performed well in CR's tests, especially at concentrations of 30 percent. It's registered with the EPA as a biopesticide and is safe when used as directed, according to the CDC and EPA.

For areas with prevalent tick-borne or mosquito-borne illnesses, DEET is still the "gold standard" for insect repellent, says Dr. Kassouf. However, if you're concerned about using DEET, natural bug sprays like citronella and lemon eucalyptus oil may be helpful for light mosquito duty.

For children, it's essential to choose the right type and concentration of repellent. The American Academy of Pediatrics recommends using repellents with a concentration of 10% DEET or less for children over 2 months old. Always follow the product label instructions and take into account the amount of time the child will be outdoors and the risk of mosquito-transmitted disease in the area.

If you're looking for alternatives to DEET, picaridin is a great option. It's a repellent modeled after a molecule found in pepper plants and has been on the U.S. market since 2005.

Picaridin has done well in Consumer Reports' tests, with spray products containing at least 20 percent picaridin working as well as or better than some DEET-based ones. Specifically, it's been shown to be safe and effective, and the World Health Organization and the CDC recommend it.

Oil of lemon eucalyptus (OLE) is another active ingredient that's done well in CR's tests, especially at concentrations of 30 percent. It's registered with the EPA as a biopesticide, meaning it's subject to at least some testing for safety and efficacy.

However, OLE is not recommended for children younger than 3, as it hasn't been well studied in this group. But for everyone else, when used as directed, the CDC and EPA agree that it's safe and works well.

Some natural bug sprays, like citronella and lemon eucalyptus oil, might be helpful for light mosquito duty. But if you're in an area with prevalent tick-borne or mosquito-borne illnesses, you might want to look beyond all-natural options.

It's worth noting that plant oil-based repellents are generally effective for a shorter time than DEET-based products, usually less than about two hours.

Consider reading: Patchouli Oil Mosquito Repellent

Using repellents on children can be a bit tricky, but with some guidance, you can keep them safe and protected from mosquito bites.

The American Academy of Pediatrics recommends using insect repellents containing DEET on children over 2 years of age.

For younger children, the AAP suggests using repellents with low concentrations of DEET, specifically 10% or less, on infants over 2 months old.

If you're concerned about using DEET or other products on your child, consider consulting your healthcare provider or the National Pesticide Information Center (NPIC) for advice.

To apply repellent safely, always follow the product label instructions and take a few precautions. Here's a quick rundown of how to use repellent on children:

Remember, repellents are just one part of the solution to avoiding mosquito bites. Dressing your child in long pants and long sleeves while outdoors can also make a big difference.

The CDC has not updated its recommendations for sunscreen usage.

It's safe to use sunscreen and insect repellent containing DEET at the same time.

Just remember to apply sunscreen first, then insect repellent containing DEET, to ensure each product works as intended.

Follow the instructions on the package for proper application of each product.

Using DEET repellents can have some health risks if not used properly. No repellent is 100 percent safe, and all repellents must be used carefully.

Use of DEET concentrations above 50 percent has been associated with increased skin irritation and similar reactions. In very rare circumstances, slurred speech, confusion, and seizures have been associated with the use of DEET, particularly in children.

The risk of experiencing any adverse health effects is reduced when products containing DEET are used according to label instructions and concentrated DEET products are avoided.

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Deet is generally safe for the environment, as it's broken down by sunlight and other chemicals in the air within 5 hours. This breakdown process significantly reduces the amount of deet that remains in the atmosphere.

The majority of deet that ends up in aquatic systems comes from our skin and clothing, which can release the chemical when we shower, bathe, or wash our clothing. This is a concern, but deet is degraded by aerobic microorganisms in water, which helps to break it down.

The good news is that deet doesn't stay in the environment for very long, making it a relatively safe choice for pest control.

DEET can dissolve some watch crystals and plastics, which can be a problem if you're using it on a watch or other accessories.

It's also not compatible with rayon, acetate, or dynel clothing, so be careful what you wear when applying DEET.

DEET can act as a plasticizer by remaining inside some formerly hard plastics, leaving them softened and more flexible.

This means that if you apply DEET to a plastic item, it may become more prone to damage or deformation over time.

DEET can also damage painted or varnished surfaces, including nail polish.

DEET can be toxic to fish and insects that live in freshwater, but only at extremely high levels. The level of DEET that kills half of them is about 75,000 times greater than the highest concentration found in waste water or streams.

DEET is not considered to be very toxic to birds.

In the environment, DEET can be broken down by microbes like bacteria and fungi, which reduces its toxicity.

Using DEET safely is crucial to get the most out of its bug-repelling power.

To start, it's essential to use the right concentration of DEET. Research shows that products with 25 to 30 percent DEET typically provide several hours of protection, and there's no need to use 100 percent DEET.

Applying the repellent properly is also key. Spray it on your hands, then rub it on your face, and avoid spraying it near your eyes or mouth. It's also a good idea to spray your clothing, especially if you'll be out in mosquito- or tick-infested areas for a long stretch.

Here are some additional tips to keep in mind:

Remember to wash the repellent off your skin when you come back indoors for the day or at the very least before bedtime.

You can use DEET-based products safely by following a few key tips. The concentration of active ingredient has an impact on how long the compound lasts, not on how well it works. Products containing 25 to 30 percent DEET typically provide at least several hours of protection.

Apply the repellent properly by spraying it on your hands and then rubbing it on your face, avoiding your eyes and mouth. Don't let young children apply repellent themselves, and apply it only to exposed skin, not to skin that will be covered by clothing. You can spray your clothing as well, especially if you're going on a hike or plan to be out in mosquito- or tick-infested areas for a long stretch.

There's no hard-and-fast rule on what age it's safe to use insect repellents on babies, but experts suggest using caution when considering them for infants. The CDC advises protecting babies that young by draping mosquito netting with elastic edges around their strollers or carriers.

A little DEET goes a long way: higher concentrations don't work better, they just last longer. If you're taking a short hike or spending an hour by a bonfire, use products with lower DEET concentrations.

Limit your exposure by covering up with pants and long sleeves to minimize the amount of skin exposed to bug sprays and bugs. Avoid putting repellent on cuts or irritated skin, and apply spray in well-ventilated areas to avoid breathing in a DEET cloud.

Here's a quick guide to DEET concentrations and their typical duration of protection:

Unless you're out all day in a bug-infested forest, you probably don't need to re-apply DEET. Skip the bug spray/sunscreen combos, too, as you'll definitely want to touch up your SPF at some point.

For your interest: Deet Bug Spray Ticks

Using a combination sunscreen and insect repellent product is not recommended by the CDC. This is because the instructions for safe use of DEET and safe use of sunscreen are different.

DEET does not need to be reapplied as frequently as sunscreen. In fact, following the product instructions for each product will give you the best results.

You don't need to reapply insect repellent every time you reapply sunscreen. Just stick to the package instructions for each product.

The EPA has evaluated the safety of using DEET and sunscreen together and has found it to be safe. However, the CDC still recommends using two separate products to avoid confusion and ensure safe use.

The rare adverse reactions to DEET have generally occurred when people don't follow the product instructions. So, make sure to read and follow the labels carefully.

Researchers have studied the safety of DEET in pregnant women, with a trial finding that DEET crossed the placenta but showed no increase in birth defects or problems with the survival of the young.

A trial was conducted on women using DEET to prevent malaria during pregnancy, with 20% DEET used on their legs and arms each day.

DEET has been found to be effective against a variety of invertebrates, including ticks, flies, mosquitoes, and some parasitic worms.

A 2018 systematic review found that DEET and icaridin are equally preferred mosquito repellents, with 50% DEET offering longer protection but not available in some countries.

DEET has been shown to be safe in pregnant women when used as directed, with no further problems in the first year of life.

A product with 20% DEET was used by women in the trial, and DEET was found in 8% of the cord blood samples.