Do Natural Insect Repellents Really Work?
Oct 21, 2015
Mozzies. They're as Australian as flies at a barbie, but did you know that the mosquito is actually the most dangerous animal on the planet? It's true. Mozzies kill more than 725,000 people every year. Mosquitoes carry diseases like dengue fever, Ross River fever, Barmah Forest virus, Japanese encephalitis, and of course, malaria. They're reasonably rare in Australia, but if you're travelling overseas, these diseases are a real problem. Given that we're all about natural around here, should you be using a natural insect repellent?
Insect Repellents in Australia
The APVMA (Australian Pesticides and Veterinary Medicines Authority) registers and approves insect repellents in Australia. Like sunscreens, insect repellents will only be approved if they contain registered active ingredients. There aren't that many registered active ingredients that are approved for use in insect repellents. DEET is one, of course, and so is Picaridin. Another one is PMD, which is a synthetic derivative of oil of lemon eucalyptus. So far, so synthetic. However, given that a mosquito borne disease can cause serious illness or even death, surely the most important factor here is how well the ingredients actually work?
How Safe is DEET?
The EWG did a comprehensive study in 2013 on insect repelling chemicals, and came to the conclusion that if it's DEET vs disease, choose DEET every time. While DEET probably isn't an ingredient that you'd choose to slather on yourself, it's not as toxic as you may have been led to believe. It's approved by the World Health Organisation, the Centre for Disease Control, the American Academy of Pediatrics, and of course, the APVMA. The EPA did a review of the toxicity of DEET in 1998 and again in 2014 and came to the conclusion that normal use of DEET does not represent a health concern.
How Safe is Picaridin?
The EWG found that Picaridin is a good alternative to DEET. It works as well as DEET in repelling insects for at least 8 hours in a concentration of 10%. However, it hasn't been tested as much and hasn't been available for as long as DEET. It doesn't seem to irritate the skin and eyes like DEET, and it's recommended as effective by the WHO. The EPA found that Picaridin isn't carcinogenic, has low toxicity when used on the skin, and has low toxicity for children under 12.
Do essential oils repel mosquitoes?
Generally in Australia, getting bitten by a mozzie is annoying. It itches, and at worst, you might have an allergic reaction. But one bite probably isn't going to do you much harm. If you're in an area with malaria, though, one bite is enough to transmit the disease. So maximum effectiveness becomes very important. Some natural essential oils work to repel mosquitoes and bugs, like citronella, lavender, peppermint and melaleuca oils. The problem is that they provide significantly less protection than DEET or Picaridin. Citronella (Poaceae) based insect repellents can protect for about 2 hours, but the formulation of the repellent is very important. It depends on what kind of citronella you're using, and the percentage of citronella oil in the formulation. It also depends on what kind of mosquito you're trying to repel. Different essential oils repel different kinds of mosquitos. DEET and Picaridin repel a wide range of mosquitos, and are effective for much longer than essential oils. Essential oils also have their other problems. They're too strong to be applied undiluted, and many of them are allergenic. If you're going to use an essential oil based repellent, make sure that you patch test it first, to make sure you don't have any reactions to it.