DEET Alternatives for Mosquito Repellents

Finally! There are natural alternatives to DEET (N, N-diethyl-m-toluamide) that actually work.

Aedes aegypti mosquitoes carry Dengue fever in Costa Rica

Lemon Eucalyptus Oil

Lemon Eucalyptus Oil (para-menthane-3,8-diol) is an excellent option if you can stand the smell. The aromatic odor is actually quite pleasant when it’s a faint whiff but cram five repellent coated people in a hot car and you’ll need all the windows down. Overall Winner – skip the results and just buy Lemon Eucalyptus at Amazon ;-)

Picaridin

Picaridin was developed by the German pharmaceutical giant Bayer in the eighties, has been used in Europe for years and was recently approved by the EPA as an insect repellent (buy Picaridin on Amazon).

Although it may sound like it should, (RS)-sec-butyl 2-(2-hydroxyethyl)piperidine-1-carboxylate (picaridin) doesn’t smell like a cross between the back of a drawer in a high school organic chemistry lab and an oil refinery. It’s nearly odorless and colorless, not oily and has only a vague flavor of dish soap.

Field Tests of Alternative Mosquito Repellent

Concentration variants are now available for Picaridin (from 7% – 24% solutions). We compared the spray on with the disposable wipes and found the protection the same but the wipes easier to use especially to get complete coverage on children. 7% was very ineffective after a few minutes but 20% Picaridin works as well as similar concentrations of DEET.

Lemon Eucalyptus seems to always be 30%.

The tests were far from scientific but they convinced me. Six adults and three children (age 2-6) gave up DEET for six days of camping, biking, hiking and fishing and counted a total of nine bites at the end. Most were thought to be due to incomplete coverage or inadequate reapplication.

As a control I washed the repellent off my arms and torso and got three bites in about ten minutes.

A few things we noticed

Lemon Eucalyptus lasts almost as long as DEET. You need to reapply every 2-4 hours if you’re just hanging out and more if you’re active. If you can’t smell it any longer then you should have put more on about half an hour ago…
Picaridin lasts a shorter time than a similar concentration of DEET. You need to reapply every 30-90 minutes. Subsequent applications seemed to last a bit longer (maybe an hour or two) so you might wait till the little buggers start hovering again.
It seems to take more Picaridin than DEET to get the same area of skin covered. Perhaps this is because it’s not oily like DEET and doesn’t spread as well. In any case I’d recommend applying a little more generously at first and backing off as you get used to using it. As mentioned above the wipes were much easier for applying to kids.
Wash your hands before eating. Picaridin doesn’t have much odor. I’ve always relied on the distinctive stench of DEET to remind me not to get my hands near my mouth or eyes.
Water resistance whether from wading across streams or heavy sweat seemed reasonable.

Overall Winner – Lemon Eucalyptus Oil (buy on Amazon)

What about Other Natural Mosquito Repellents like Citronella?

Mosquitoes have been my arch nemesis since I started hiking and camping fifty odd years ago and I’ve tried every new repellent that’s come along. Avoiding bites is even more important in now with the introduction of the African diseases Chikungunya and Zika to Costa Rica’s mosquito population.

Asian Tiger mosquito or Forest mosquito (Aedes albopictus) are active all day and along with the Dengue vector Aedes aegypti they’re bringing Zika to warm climates in the western hemisphere

You can pluck citronella fruit straight from the tree and rub it on since it grows wild in Costa Rica. Unfortunately our experience agreed with independent studies that showed citronella oil while approximately as effective as DEET when first applied only lasts a few minutes.

We haven’t had very good luck with gerinol either. Independent studies have shown it to be almost as effective as DEET for at least 30 minutes but it seemed to attract mosquitoes to me.

IR3535 (3-[N-butyl-N-acetyl]-aminopropionic acid, ethyl ester) is another “biopesticide repellent,” meaning synthetic or extracted chemicals from natural sources that the EPA has approved as mosquito repellents. It didn’t work for me and I had to switch to DEET within a few minutes.

In general we found that the natural repellents did reduce the number of mosquito bites for a short time but we weren’t willing to reapply every few minutes. The effectiveness of natural repellents seems to vary a lot depending on the person using them so you may want to give some of the above a try.

Clothing and Other Ways to Prevent Mosquito Bites

Permethrin

Long sleeves and pants are often recommended and they don’t hurt but anywhere they come in contact with skin the mosquitoes will bite through. We’ve never had much luck unless we treated the clothes (and tents, mosquito nets etc.) with insecticide.

The most effective treatment for clothing that we’ve found is 0.5% Permethrin ((3 phenoxyphenyl) methyl 3-(2,2-dichloroethenyl) 2,2-dimethylcyclopropanecarboxylate) which seems to work quite well for about 2-4 weeks (and 4-6 washings) after treatment. Recommended for clothing! – buy at Amazon

Never apply permethrin directly to skin. It is toxic in solution but safe after it drys and binds to fabric.

Diet

Many people recommend dietary supplements as an effective deterrent to mosquitoes. I’ve tried overdosing on vitamin B complex, vitamin D, Gin, garlic and may more but I might as well have eaten a cow paddy because it was all B.S. There is no scientific evidence that diet has a significant impact. Is it worth a try? Sure, there are many people who swear it works but get some lemon eucalyptus as a backup.

Magic

Bracelets, magnets, carbon dioxide generators and other magic charms are marketed to travelers trying to avoid DEET. Are they worth a try? In our opinion no, but if you insist be sure to have a repellent backup plan.

Are Natural Products Safer?

Well, they may sound safer at first, but consider this list of 100% natural ingredients.

3,3-dimethylbicycloheptan-2-one
phospholipase A2
(Z)-methyl isoeugenol
muurolene

Three of the above compounds are some of the fifty-plus components identified so far from citronella oil and one (phospholipase A2) is an active component of cobra venom.

If you knew that, then you may actually have some idea of what you’re rubbing on when you use a natural repellent. The toxicity and potential carcinogenicity of natural repellents is not rigorously tested because they are not highly regulated like synthetic compounds.

Natural repellents may be safer but no one has really checked. DEET and picaridin on the other hand have undergone exhaustive testing by the EPA and others and found to have only a few minor associated risks which are far outweighed by their effectiveness in preventing serious diseases like malaria, west nile and dengue.