And what kind do I use? I do make my own, from time to time. But when the biters are bad, I go for something with DEET on the label. DEET is short for N,N-diethyl-m-toluamide and is a member of the toluene chemical family. Toluene is an organic solvent which can be absorbed through human skin, where it passes into the blood stream. The Medical Sciences Bulletin, published by Pharmaceutical Information Associates Ltd. reports, "Up to 56% of DEET applied topically penetrates intact human skin and 17% is absorbed into the bloodstream." Blood concentrations of about 3 mg per liter have been reported several hours after DEET repellent was applied to the skin as directed. DEET is also absorbed by the internal organs.
The most serious concerns about DEET are its alleged effects on the central nervous system. One Duke University study showed that lab animals exposed to the equivalent of the average human doses of DEET performed far worse than untreated animals in motor skills tests. The study also found that combined exposure to DEET and permethrin can lead to both motor deficits, and learning and memory dysfunction. If you do decide to use DEET, its best to wear long sleeves and long pants, when possible, and apply the repellent to your clothing rather than skin to reduce your exposure. Use the DEET based products sparingly, as saturation does not increase their efficiency. Never inhale DEET repellents (hold your breath while spraying). Repellent-treated clothes should be washed, or kept outside of living areas to reduce your exposure.
Should we even be using these chemicals? I say yes. It works, and it’s easier for your body to get rid of chemicals than an insect borne disease.
Are there safer options? Sort of… There are a number of effective, less toxic insect repellents on the market. You can also whip up your own with essential oils which may be available at your local health food store. I’ll mix 20 drops of tea tree oil and 20 drops of lavender oil with a few ounces of vinegar, and pour the mix into a spray bottle for backyard protection. These natural repellents need to be applied more frequently than DEET based repellents, but they do not carry the same alleged health risks. Two commercial botanical repellents which performed particularly well in a Florida study were Repel Lemon Eucalyptus Lotion Insect Repellent (also marketed as FiteBite Plant Based Insect Repellent) which protected for 120 minutes, and Bite Blocker for Kids, a 2% soybean oil formula, which was effective for 95 minutes. Citronella products in the study provided about 30-40 minutes of protection. Look for repellents based on essential oils that include citronella, tea tree, pennyroyal, cedar and eucalyptus, but be aware that these are volatile oils which may trigger allergic reactions in some people, particularly the chemically sensitive. For those really sensitive folks, mesh “Bug Shirts” and head nets are an excellent, non-toxic method of protection. This baggy mesh “over clothing” is also an excellent mate repellent, so you’ve got that going for you too!
And if that’s not enough, you can:
Follow Tim on Twitter @timmacwelch
Take one of his survival classes at www.advancedsurvivaltraining.com
and check out more of MacWelch’s outdoor skills and survival articles at Outdoor Life Magazine’s survival site, The Survivalist.