Mosquito Repellant: Is DEET the only option?  (No, there are safer choices!) 

Going on camping trips and just generally living in the woods for most of my life now, I am very familiar with mosquito repellant.  I was told that more DEET = less mosquitoes.  What exactly is DEET ?  

According to pesticides.org, “DEET is a repellent used by almost one-third of the U.S. population every year. It is one of the few pesticides applied directly to skin and clothing.”  It was developed during WWII by the US Army as a repellant and has been in use as a pesticide since 1957.  Just because it’s been used so long, does not mean it’s safe, however!

DEET has scary effects on animals, some children, and the cells and DNA in our bodies.  In lab tests, animals subjected to DEET lost much of their ability to climb, grip, and reproduce in normal ways.  It is debilitating and fatal to fish.  Children may have seizures at even low concentrations (less than 20%), and experiments with our own brain cells show that it kills them.  It’s not something I’ll want to apply again to anyone in my family!  

Permethrin is a different mosquito repellant that is marketed and sold as a fabric treatment for tents, clothing and camping gear like backpacks and used as an outdoor soil treatment for termites; it is a synthetic pyrethroid, which is a class of neurotoxins.  It behaves in insects similarly to the insecticide DDT.  Permethrin does not decay quickly in soil (it is commonly sprayed on the ground and around homes).  Besides being a possible carcinogen, it affects the immune system, hormones, and different organs such as the liver and lungs.  According to laboratory studies on rats, “children may be more sensitive to permethrin than adults,” (pesticide.org).  Why put yourself into close contact with a neurotoxin, just to avoid termites or insects?

I believe there is “kryptonite” for every pest–we just have to discover them.  The following repellent active ingredients work by masking the personal scent that mosquitoes use to target us as prey.  Some are manufactured and some are natural extracts.

• Picaridin is a synthetic imitation of piperine, an extract from plants used to make black pepper.  It is in the original formulation of Skin So Soft, which was passed around many Girl Scout Troops and made its way onto our family camping and fishing trips too.  According to the National Pesticide Information Center (NPIC), Picaridin has had very few allergic reactions, was not shown to cause cancer, and is generally safe.  
• Due to the anecdotal (not studied) evidence that Skin So Soft repels mosquitoes, Avon produced a Bug Repellant that contains IR3535 as its active ingredient, which is a chemical that is structurally similar to the naturally occurring amino acid B-alanine (ewg.org). It is similar to or slightly less effective than DEET or Picaridin on mosquitoes, but almost twice the mean protection time of these products against deer ticks (which are carriers of Lyme’s Disease).  It can be very irritating to the eyes, but has no other health risks.
• Oil of Lemon Eucalyptus is an extract of a species of Australian eucalyptus tree.  This extract is refined in order to concentrate the chemical that repels bugs, para-menthane-3,8-diol, or PMD.  PMD is used by brand names Repel and Cutter at 30% Oil of Lemon Eucalyptus or 20% PMD.  According to beyondpesticides.org, PMD was tested in Africa against mosquitoes that are known to cause malaria, and it “gave complete protection from biting for between 6 and 7.75 hours”, and it was equally effective as lower concentrations of DEET.  PMD has reportedly few allergic skin reactions but it is an eye irritant.  Because it has not been studied on young animals, it’s not advised to use on children under 3. 
• Essential oils: Clove or Thyme oil at 50% concentrations were the most effective in this study of 5 oils, however they can be irritating to the skin and not pleasant to every user at these high concentrations.  In this study, clove oil was studied along with citronella, patchouli, and makaen (Zanthoxylum limonella), and clove oil performed the best, with undiluted clove oil giving 2-4 hours of complete repellency.  This study also concluded that full-strength oils perform the best, but adding vanillin increased the time of repellency.  VerywellHealth.com gives a list of more oils and their respective benefits and cautions. 

These are the ACTIVE ingredients.  We note that  there is always a “carrier” (whether it’s called inert or inactive, these are the ingredient(s) that dilute and aid in application of the active ingredient) and not every product discloses the full list of ingredients.  It’s always best to check the Material Safety Data Sheet (MSDS) for a product you are considering.  These are usually found at the bottom of the manufacturer’s home page.  

• Picaridin products tend to have less disclosure about carrier ingredients: 
  • Sawyer Products 20% Picaridin Insect Repellent and Naturapel’s Picaridin Insect Repellent both contain Polyethylene Glycol (PEG).  Despite the wide use of PEG in the cosmetics industry, it can be contaminated with carcinogens and if used on broken skin, a cause for irritation and systemic toxicity (David Suzuki Foundation). 
  • RangerReady Repellents Picaridin 20% contain propylene glycol, which is a penetration enhancer and found to provoke skin irritations in people with eczema and other skin allergies (ewg.org)
  • Earthkind StayAway Mosquitoes is a Picaridin formula made with small parts of ethanol, glycerin (both non-toxic), and mainly water, but 10% undisclosed ingredients (it could be a fragrance or combination of ingredients). 
• Murphy’s Naturals is a great choice because this company clearly states that the carrier in their Lemon Eucalyptus Oil Insect Repellant Spray is deionized water and corn ethanol (alcohol made from corn). 
• Wondercide has a range of repellants made with different essential oils (for personal scent preferences, not efficacy).  They are safe for kids and adults, with no artificial dyes or fragrances.
• Anyone who travels or has young children would appreciate the convenience of Aunt Fannie’s Mosquito Repellent Wipes, the ingredients of which are clearly stated on the front of the package.  The main active ingredients are citronella oils and cedarwood oil, with peppermint, lemongrass and geranium.  While cedarwood oil did not fare well alone as a repellent in this study, the combination in Aunt Fannies seems to work as they are blessed in good reviews and sales. 
• Kinfield’s Golden Hour spray ($22 for 3 oz) is priced at a premium, but its reviews are too good to ignore.  Made of active ingredients citronella oil, lemongrass oil and clove oil, with inactive ingredients isopropyl alcohol, lauric acid, water and vanillin, the scent is light with citrus and vanilla.

Has anyone found any new or different ingredients or products that safely repel mosquitoes?  Let us know!

Photo by Bima Wahyu on Unsplash