Introduction

What's the story with DEET?

The Centers for Disease Control and Prevention (CDC) recommends using insect repellent containing active ingredients that have been registered by the Environmental Protection Agency (EPA). Products containing DEET, picaridin, IR3535 (all man-made chemical options) and oil of lemon eucalyptus (a natural mosquito repellent) are approved by them for use on skin and clothing, which means they "can be used without posing unreasonable risk to human health or the environment." Additionally, some products containing permethrin (another man-made chemical) are registered by the EPA for use as a repellent for use on clothing and camping gear.

According to the World Health Organization (WHO), DEET is the "best available product, repelling a wide variety of insects, ticks and mites and generally lasting longer than the other repellents." However, the safety of DEET has been debated on and off for years. The EPA conducted a safety review in 1998 and concluded that DEET doesn't pose a health risk when used according to the application directions. However, the American Academy of Pediatrics (AAP) recommends not using products containing DEET on infants younger than 2 months old and not exceeding a concentration of 30 percent DEET on children above that age.

But even though DEET passed muster with the EPA, there's plenty of skepticism regarding its safety, particularly among parents. After all, DEET can melt plastic and some fabrics, and some studies have shown high concentrations of the chemical to cause neurological damage in mice. It also has a strong chemical smell and needs to be washed off after returning indoors to prevent prolonged skin absorption. So while DEET is certainly a reliable and effective mosquito repellent, there's a lot of consumer interest in alternatives.

When it comes to DEET alternatives, we found that effectiveness can vary from person to person. Scientific studies confirm some people do attract mosquitoes more than others and, in the same way, research shows that insect repellents are more effective on some people than on others. The way a product smells and feels on the skin can also be a factor. This is a very personal consideration that we found often elicits mixed opinions in reviews. For that reason, the best insect repellent reviews employ many testers and report the minimum and maximum protection time, not just the average.

Overall, ConsumerReports.org offers the most recent and comprehensive testing of bug repellents. Editors there enlist four volunteers to gauge effectiveness of 10 products -- five containing DEET, three with natural plant oils and one using IR3535 (the chemical ethyl butylacetylaminopropionate) as its active ingredient. Bug repellers are ranked on the duration of their effectiveness against two species of mosquitoes as well as ticks. More than half of the products return nearly identical results when tested over an eight-hour period. Editors also assess whether the ingredients damage other materials and comment on the mosquito repellents' odor and feel on the skin. Editors of Which? magazine, a U.K. publication comparable to ConsumerReports.org, also recently evaluated 19 bug repellents, but they only use a single test subject, and most of the products aren't available in the U.S.

Medical and academic studies also offer some interesting insights into the active ingredients. For instance, a 2004 study in the Journal of Medical Entomology compared the effectiveness of eight natural and four chemical insect repellents. The laboratory test used mosquitoes but not ticks. One drawback: Only two test subjects were used. Another study conducted by Mark Fradin and John Day published in The New England Journal of Medicine in 2002 also compared an impressive lineup of 16 mosquito repellers and 15 test subjects. Although dated, most of the mosquito repellents are still sold today or have just a small change in the percentage of DEET. The study included a nice mix of DEET and non-DEET bug repellers and is one of the few studies to evaluate repellent wristbands.

The Canada Communicable Disease Report contains a 2004 study conducted for the purpose of recommending products for preventing and treating malaria. A chart comparing the types of insect repellents emphasizes a correlation between a higher DEET level and a longer duration of effectiveness. Natural insect repellents containing oil of lemon eucalyptus, soybean oil and citronella oil are also discussed.

Reviews that conduct testing in the outdoors rather than in a laboratory setting also reveal some intriguing results. In one test, a writer at Slate.com enlists the help of friends to test nine mosquito repellents. Unfortunately, each mosquito repeller is only tested on one subject and the duration of the test is limited to one evening, so we don't know the maximum length of protection. However, the writer does offer some insights into how each product smells and feels on the skin. A 2008 review at Grist.org, an environmental website, compares five natural insect repellents. However, the writer opts to focus on the products' scent and feel rather than on their effectiveness. A review in Backpacker magazine also discusses the odor of each bug repeller along with how it feels on the skin.

Other reviews that target only one or two bug repellents aren't as helpful. Good Housekeeping magazine editors spotlight two insect repellents -- Off! Deep Woods and Cutter Skinsations. Although the review is conducted by scientists from the University of Florida, it's from 2002. A separate article at Good Housekeeping provides information about five different options for creating an insect barrier in the backyard. About.com provides a list of 10 top insect repellents, plus many other reviews of a single product..

Australia's Consumer magazine, a consumer products testing organization similar to ConsumerReports.org, chose to limit their review to non-DEET bug repellents. This 2009 review compares five DEET alternatives on four different people. However, the brands included in the test are not sold in the U.S. Still, editors provide a useful explanation of the various types of mosquito repellents and give advice for adequate insect protection when traveling overseas.

Beyond this, we didn't find an overwhelming amount of insect repellent reviews by users. Drugstore.com, Amazon.com and REI.com offer the most feedback among online retailers. Viewpoints.com also offers a limited number of user reviews on a variety of mosquito repellents.