Health Link Canada claims that "your best protection is insect repellent with DEET. Used as directed, DEET has an excellent safety record. Products with lemon eucalyptus oil are effective for shorter periods of time". Does it mean that the best bug repellent is a repellent that contains DEET? It's true that DEET provides good protection against ticks and mosquitoes. But its safety is questionable. The good news is that there are natural options that are even more effective than DEET, such as products containing lemon eucalyptus essential oil.
Is DEET the best bug repellent?
DEET (N, N-diethyl-meta-toluamide) works by blocking the insect’s senses so that it is not attracted to human sweat and breath. Many studies show that it is the most effective insect repellent.
Its effectiveness depends on its concentration : "100% DEET was found to offer up to 12 hours of protection while several lower concentration DEET formulations (20%-34%) offered 3-6 hours of protection’".
But is it safe to use on a regular basis? Products containing less than 30% of DEET are supposed to be safe for children from 2 months old. There is no indication that DEET poses a risk for pregnant or nursing mothers.
Yet, there are side effects associated to DEET. I still wonder how a solvent that can dissolve plastic and peels paint is not toxic for our body. DEET is actually a moderate chemical pesticide. Originally it was used as a pesticide for farm fields and was developed by the United States army during World War II. Do we really want such a chemical to penetrate our bloodstream through our skin?
Manufacturers advise that DEET should not be used under clothing or on damaged skin, because it can irritate the skin. Cases of serious reactions to products containing DEET have actually been reported when using for multiple days without washing the skin in between use.
Other studies show that DEET is slightly toxic for the environment, especially in water sources.
Answer: DEET may be an effective insect repellent, but its safety is still questionable.
Is lemon eucalyptus the safest and most effective natural repellent?
Studies show that lemon eucalyptus (eucalyptus citriodora) repellents are highly effective against mosquitoes. Lemon eucalyptus is one of the best bug repellents especially if you don't want to use DEET for the reasons explained above.
Although products containing eucalyptus oil should not be used on children under 3 years of age, it appears to be a safer choice when applied on the skin and the most effective natural way to repel insects.
An investigation by the product-testing group Consumer Reports finds that there are natural options that are even more effective than DEET, such as products containing picaridin and lemon eucalyptus. Repel Lemon Eucalyptusis one of the winning bug repellents.
Look first for products with 20 percent picaridin or 30 percent oil of lemon eucalyptus. We think they’re safer than those with deet. If deet is your only option, aim for a concentration of about 15 percent, which even outperformed the product with 25 percent. In concentrations more than 30 percent, deet might be dangerous." - Consumer Report
Answer: Products containing picaridin and oil of lemon eucalyptus are the most effective insect repellents. Both are chemically synthesized ingredients but they are more similar to natural compounds than DEET. They also have fewer side effects.
Are natural mosquito repellents better alternatives and do they work?
Insect repellents using essential oils such as citronella, lemongrass, and rosemary, may be helpful to repel mosquitoes. But they are not as effective as insect repellents with chemically synthesized ingredients (including picaridin and oil of lemon eucalyptus).
Neem oil is also effective against mosquitoes. Neem oil deters them and prevents them from feeding.
However, most natural mosquito repellent products don't last more than 1 hour against aedes mosquitoes, aggressive biters that can transmit chikungunya, dengue or zika virus.
Answer: natural mosquito repellents containing essential oils such as citronella, lemongrass or rosemary, are not as effective. Remember to reapply natural mosquito repellents more often because they are not quite as long lasting.
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What's the best bug repellent for babies and pregnant women?
Wearing protective clothing is certainly the best alternative especially for babies and pregnant women, but that's not always an option in the heat of summer.
Apparently, eating garlic or foods rich in vitamin B1 does not really provide protection against mosquitoes.
So try to avoid what actually attracts mosquitoes:
- Dark clothing, floral or fruity fragrances, moisture
- Cooler temperatures of the extremities
- Lactic acid produced by the body after exercising or after eating certain foods such as salty foods or high-potassium foods
- Carbon dioxide from a source of fire or even when you are hot or have been exercising
Answer: If you are in a place with a high rate of insect diseases (e.g. West Nile virus, Lyme disease, Dengue fever, zika, Chikungunya), or you experience severe allergic reactions to bites and stings, it might be worth using DEET products. Otherwise, on a regular basis, use DEET-free products and safer alternatives containing lemon eucalyptus.