Toxicologist Mary Beth Genter, PhD, an associate professor in the University of Cincinnati College of Medicine environmental health department, cautions people to remember that insect repellents are, by definition, pesticides so caution and proper application are important to avoid negatively impacting human health. The U.S. Environmental Protection Agency (EPA) defines pesticides as chemicals that are designed to “prevent, destroy, repel, or mitigating any forms of life declared to be pests.”
The most common and effective bug repellent is DEET (N, N-diethyl-meta-toluamide), a chemical developed by the U.S. Army in 1946 to help protect soldiers on the battlefield. It was introduced to the public consumer market in 1957.
“DEET is believed to work by confusing insects so that they cannot recognize humans as something they want to bite. In the grand scheme of things, the chemical is relatively safe,” says Genter. “Like any pesticide, though, consumers should use caution and follow the application instructions specifically to avoid harm.”
Health concerns with DEET-containing bug repellents stem from the skin’s barrier function, particularly with young children. The American Academy of Pediatrics recommends abstaining from using bug repellent in children under 2 months of age and restricting use in children under the age of 10 to products with a DEET concentration of 10 percent or less. It is also recommended that DEET not be applied to children’s hands or around their mouths to avoid ingestion.
The EPA conducted an extensive safety review of DEET in 1998 and concluded that—when used as instructed—DEET was an effective topical bug repellent safe for human use.
“The best advice is to use pesticide-containing products in moderation and following the application instructions specifically,” adds Genter.
Although most people are driven to bug repellents to avoid the irritating itch and discomfort that follows a bite, the real benefit is disease prevention. According to the EPA, mosquitoes can transmit diseases like St. Louis encephalitis and West Nile virus. Ticks can transmit Lyme disease, Rocky Mountain spotted fever, and Ehrlichiosis—all of which have serious health consequences.
“Creating a home environment that discourages tick and mosquito development is one of the best means of prevention. This includes eliminating sources of standing water where mosquito larvae thrive—containers, gutters, fountains—and keeping your lawn and fence lines trimmed. Ticks like to hang out in tall weeds and grass,” says Genter.
Tips for the safe use of bug repellent include:
- Wash treated skin immediately with soap and water upon going indoors.
- Do not apply repellent spray or lotion to open wounds or cuts—this raises the potential that the chemical will penetrate the skin’s barrier and begin circulating throughout the body.
- Apply repellent to exposed skin and clothing. Do not apply under clothing.
- Avoid over-application by reading and following the product’s label guidelines.
- Wash exposed clothing before re-wearing.
- To apply to face, spray on hands then apply manually versus spraying directly.
- Do not spray in enclosed areas.
- Keep out of reach of children—adults should apply insect repellents to children.
If you choose to use bug repellents, the EPA maintains a list of registered products it certifies as both safe for humans and effective. These products will display and EPA registration number on the label. Certain “minimum risk” pesticides—including many essential oils—are not required to undergo safety and effectiveness testing and obtain EPA registration. To learn more, visit epa.gov.