When it comes to choosing the best insect repellent, you have two choices: chemical-based or natural deterrents.
Demand for natural, plant-based insect repellents and alternatives to the most powerful chemical repellent, DEET, have soared in recent years. Many parents are reluctant to put chemical sprays on their kids -- though DEET is deemed safe for kids over 2 months old -- while many plant-based repellents (like those containing oil of lemon eucalyptus) aren't safe for babies and toddlers.
The anti-DEET trend isn't as popular with outdoor enthusiasts delving into mosquito-infested tropical climates or on a hike in the deep backwoods, however. Many campers, hunters and overseas travelers are more concerned with warding off mosquitoes and bugs that could carry malaria, West Nile, Lyme disease or a host of other insect-borne diseases, and seek out the strongest and most effective repellents on the market.
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, which is popular in Europe; IR3535 (all chemical options); and oil of lemon eucalyptus are approved for use on skin and clothing. Additionally, some products containing permethrin (another chemical) are registered by the EPA for use as a repellent for use on clothing and camping gear.
Experts say DEET isn't particularly effective against black flies, gnats, biting flies, fleas and mites - but those insects usually don't carry potentially fatal diseases. 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 recommends against 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. Canada recommends using less than 10 percent DEET on children under 12.
Even though DEET passes muster with the EPA, there's plenty of consumer skepticism regarding its safety. 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.
Public health experts recommend using extended-duration DEET if you might be exposed to insect-borne disease like malaria, but for a summer outdoor picnic or hike in less risky areas, insect repellents containing DEET alternatives are effective. The Environmental Protection Agency has a useful search tool to help you decide which type of repellent best suits your needs.
Herbal-based repellents like citronella, lemon eucalyptus, soybean and other natural oils are all popular options. Their effectiveness varies, but lemon eucalyptus oil seems especially good at repelling mosquitoes and ticks, according to Canadian health authorities. One issue with herbal repellents is that their scent can be offensive -- same with DEET.
A number of professional organizations, including Consumer Reports and Consumer magazine (a New Zealand publication) test and review insect repellents. These reviews helped determine the best reviewed picks in the following categories: best insect repellent, best insect repellent for kids, best natural insect repellent and best insect repellent for clothing and gear. Consumer feedback at Amazon.com and Drugstore.com is also valuable.