By Dr. Mercola
Biting insects can put a damper on your summer fun, not to mention potentially transmit diseases like Lyme disease
and West Nile Virus. The majority of US adults (75 percent) said they are actually more concerned about such
diseases than they are about potentially dangerous chemicals in insect repellent.1
Still, most people also told Consumer Reports that safety is important when choosing an insect repellent,
and only one-third believe products on the market are safe for adults (and only 23 percent considered them safe for
Concern is well-justified, as DEET (N,N-diethyl-
meta-toluamide) is used in hundreds of products, in concentrations of up to an astounding 100 percent. DEET has been
shown to harm brain and nervous system function.
Children are particularly at risk for subtle neurological changes because their skin more readily absorbs
chemicals in the environment, and chemicals exert more potent effects on their developing nervous systems.
DEET is not your only option for insect repellent, fortunately, and Consumer Reports tests have recently
revealed natural alternatives that may be even more effective without the harsh side effects.
Picaridin and Lemon Eucalyptus Beat DEET for Repelling Insects
Consumer Reports recruited volunteers to test out spray-on repellents made of DEET, oil of lemon eucalyptus,
picaridin, a chemical called IR3535, and products made with natural plant oils. After the repellents were applied and
allowed to sit for 30 minutes, the volunteers reached into a cage containing (disease-free) mosquitoes or ticks.
Two products emerged on top and were able to keep mosquitoes and ticks away for at least seven hours: products
that contained 20 percent picaridin or 30 percent oil of lemon eucalyptus. Picaridin resembles the natural compound
piperine, an essential oil in black pepper.
However, picaridin is not a natural compound; it's produced synthetically in the lab. According to the
Environmental Working Group (EWG), picaridin does not carry the same neurotoxicity concerns at DEET, although it has
not been tested much over the long term. They report:2
"Overall, EWG's assessment is that Picaridin is a good DEET alternative with many of the same advantages and
without the same disadvantages."
Lemon Eucalyptus Is a 'Biopesticide' Repellent
Oil of lemon eucalyptus comes from
the gum eucalyptus tree, but it is p-menthane-3,8-diol (PMD), its synthetic version with pesticidal properties, that
is used as an insect repellent. While the term "PMD" is often used interchangeably with lemon eucalyptus oil, know
that it is different from the "pure" unrefined oil, which is typically used in making fragrances.
The pure oil is not registered with the US Environmental Protection Agency (EPA) as an insect repellant. PMD or the
refined version, on the other hand, has a long history of use but only recently became important as a commercial
In 2000, the EPA registered oil of lemon eucalyptus or PMD as a "biopesticide repellent," meaning it is derived from
natural materials. Both lemon eucalyptus oil and picaridin are not actual repellents, but insteadmost likely
work by masking the environmental cues that mosquitoes use to locate their target.
Side effects of both picaridin and lemon eucalyptus include potential skin or eye irritation, and the US Food and
Drug Administration (FDA) states that picaridin should not be used on children under age 3. Urvashi Rangan, PhD,
executive director of Consumer Reports' Food Safety and Sustainability Center, said:
"They are not side-effect-free, but 'those problems are much less severe than deet…' Still, all repellents
should be used sparingly and only for the time you need them—especially on children and older people."
Why DEET-Containing Repellents Are Better Off Avoided
About 30 percent of Americans use DEET every year, but you should know that this chemical – though generally
effective in keeping away insects – can have deadly repercussions. From 1961 to 2002, the Agency for Toxic Substances
and Disease Registry reports eight deaths related to DEET exposure.
Three of these resulted from deliberate ingestion, but five of them occurred following DEET exposure to the skin
in adults and children.3
Psychological effects have also been reported including altered mental state, auditory hallucinations, and severe
In children, the most frequently reported symptoms of DEET toxicity reported to poison control centers were
lethargy, headaches, tremors, involuntary movements, seizures, and convulsions. Further, in a study of more than 140
National Park Service employees, 25 percent reported health effects they attributed to DEET, including:4
✓ Skin or mucous membrane irritation
✓ Transient numb or burning lips
✓ Difficulty concentrating
In addition, Duke University Medical Center pharmacologist Mohamed Abou-Donia spent 30 years researching the
effects of pesticides. He discovered that prolonged exposure to DEET can impair cell function in parts of your brain
-- demonstrated in the lab by death and behavioral changes in rats with frequent or prolonged DEET use. Other
potential side effects DEET exposure include:
✓ Memory loss
✓ Muscle weakness and fatigue
✓ Shortness of breath
✓ Muscle and joint pain
Another potentially harmful chemical found in many bug sprays is permethrin. This chemical is a member of the
synthetic pyrethroid family, all of which are neurotoxins.
The EPA has even deemed this chemical carcinogenic, capable of causing lung tumors, liver tumors, immune system
problems, and chromosomal abnormalities. Permethrin is also damaging to the environment, and it is particularly toxic
to bees and aquatic life. It should also be noted that permethrin is highly toxic to cats.5
Non-Chemical Options to Keep Bugs Away from Your Barbecue
Consumer Reports also tested three non-chemical options for keeping pests away from a simulated backyard barbecue:
a citronella candle, a portable diffuser with essential oils, or an oscillating pedestal fan set at its highest speed.
While neither the candle nor the diffuser showed much promise, the fan worked well, cutting mosquito landings
by 45 percent to 65 percent among those sitting near the fan.
Similar results were found from the Consumer Reports survey, which found 45 percent of people who used fans to
keep insects away reported them as "especially helpful" (compared to 31 percent of those who used candles).6
Naturally, the best way to avoid mosquito bites is to prevent coming into contact with them in the first place. You
can avoid insect bites by staying inside between dusk and dawn, which is when they are most active.
Mosquitoes are also thicker in shrubby areas and near standing water. The American Mosquito Control Association
(AMCA) recommends the "Three Ds" of protection to prevent mosquito breeding on your property:7
- Drain – Mosquitoes require water in which to breed, so carefully drain any and all sources of
standing water around your house and yard, including pet bowls, gutters, garbage and recycling bins, spare tires, bird
- Dress – Wear light colored, loose fitting clothing—long sleeved shirts and long pants, hats, and
- Defend – While the AMCA recommends using commercial repellents, I highly recommend avoiding most
chemical repellents for the reasons already discussed; try some of the natural alternatives instead, when
Bat houses are another option since bats are voracious consumers of insects, especially mosquitoes. For more on
buying a bat house or constructing one yourself, visit the Organization for Bat Conservation.8 Planting marigolds around your yard also works as a bug
repellent because the flowers give off a fragrance that bugs dislike.
Enjoy the Outdoors with These Additional Natural Repellent Options
Body temperature and skin chemicals like lactic acid attract mosquitoes, which explains why you're more likely to be
"eaten alive" when you're sweaty, such as during or after exercise, so trying to stay as cool and dry as you can may
help to some degree. Some experts also recommend supplementing with one
vitamin B1 tablet a day from April through October, and then adding 100 mg of B1 to a B100 Complex daily during
the mosquito season to make you less attractive to mosquitoes. Regularly consuming garlic
may also help protect against mosquito bites, as may the following natural insect repellants:
- Cinnamon leaf oil (one study found
it was more effective at killing mosquitoes than DEET9)
- Clear liquid vanilla extract mixed with olive
- Wash with citronella soap, and then put 100% pure citronella essential oil on your skin. Java Citronella is considered the highest quality citronella on
- Catnip oil (according to one study, this
oil is 10 times more effective than DEET10)
Another option is to use the safe solution I have formulated to repel mosquitoes, fleas, chiggers, ticks, and
other biting insects. It's a natural insect spray with a
combination of citronella, lemongrass oil,
peppermint oil, and vanillin, which is a
dynamite blend of natural plant extracts. In fact, an independent study showed my bug spray to be more effective than
a product containing 100 percent DEET. And it's safe for you, your children, and your pets. You can also try
using lemon eucalyptus oil to make a homemade insect repellent. Here is a recipe from Backpacking Spirit to try
"Make your own mosquito repellent consisted of around 10% lemon eucalyptus oil. If you are using the essential
('pure') oil, note that it does not mix with water and will therefore require a carrier oil, such as hazel, vodka, or
- Obtain an appropriately sized bottle for travel; a 100 to 200 ml bottle will be a good choice. You may also
go for a bottle that has a spritzer nozzle for easy application.
- Choose your carrier oil
- Use a measuring jug for more precise measurements.
- Think 10% essential oil. If you are using a 100 ml bottle, mix 90 ml of your chosen liquid and 10 ml of lemon
eucalyptus oil. If you are using a 200 ml bottle, mix 180 ml of liquid and 20 ml of essential oil.
- Shake the bottle thoroughly before use.
- Spritz onto skin and rub in."