Note: Insect repellents are not effective against stinging insects (bees, wasps, hornets).
|Picaridin||Chemical||Yes||Up to 8 hours|
|Oil of lemon
|Yes||Up to 6 hours|
|Plant oils (soybean,
|No||Estimated 30 min.
to 2 hours
Background: Developed in Germany by Merck in early 1980s; registered in U.S. in 1999. Chemical name: 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester. Derived from the amino acid alanine.
Effectiveness: Potential duration of effectiveness: Up to 8 hours. Refer to product label.
Safety: From the EPA: “IR3535 has been used as an insect repellent in Europe for 20 years with no substantial adverse effects. Toxicity tests show that IR3535 is not harmful when ingested, inhaled, or used on skin.” The American Academy of Pediatrics has made no recommendation on the use of IR3535.
Learn more in this IR3535 fact sheet by the EPA.
Active ingredients are what make insect repellents effective. Repellents are considered pesticides, and before most can be marketed they must be registered with the EPA.
However, 30+ active ingredients made from plant oils are exempted from EPA registration. That means they are safe for humans but not necessarily effective.
Unregistered: The EPA has a list of 31 “minimum-risk pesticides”—plant-based ingredients (both active and inert) that the agency describes as “demonstrably safe for the intended use.” Data demonstrating effectiveness, though, is not required for these ingredients. Thus repellents in this group could bill themselves as “EPA approved; all-natural.” Yet their duration of effectiveness is uncertain—believed to be between 30 minutes and 2+ hours—well short of what synthetics deliver.
Examples: Essential plant oils (lemongrass oil, cedar oil, geranium oil and many others) or food ingredients (corn oil, cloves and clove oil).
What diseases are transmitted by insects, and which insects do the transmitting? Here are links to information provided by the CDC and FDA.
Malaria. To protect international travelers from aggressive mosquitoes that carry this disease, the CDC advises the use of repellent, treated clothing and bed-netting and preventative pre-travel medication.
Other mosquito-transmitted diseases include yellow fever (a vaccine is available and may be required for entry into some countries), dengue fever, Japanese encephalitis and chikungunya fever. For current news of specific locations, visit the CDC’s travel site.
Shop REI's selection of insect repellents.
Mosquito photo courtesy of Cristi Day, REI Asheville, N.C., sales lead.
By T.D. Wood
Read Author Bio
Last updated: 02/18/2014
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