Topical repellents are usually found in spray and lotion formulas that most commonly contain DEET, a chemical approved by the U.S. Environmental Protection Agency (EPA) as the active ingredient. It is proven to prevent or decrease mosquito bites, as well as problems with ticks and chiggers. It is widely considered the most effective insect repellent available on the market. Repellents containing DEET usually are manufactured to contain up to 35% DEET (but can contain up to 100% concentrations), and, for adult use, can last up to eight hours. Products with lower concentrations of DEET can provide anywhere from one to five hours of protection. Repellents with DEET concentration of 10% to 30% are approved for use on children between the ages of 2 and 12 by the American Academy of Pediatrics.
While DEET has been tested as safe for human use, it is recommended that you avoid using DEET-based products of any concentration on infants under six months of age.
Always store insect repellents in a utility closet or similar locked structure, safely out of reach of small children.
Picaridin is a more recent addition to insect repellents found in the U.S. market. It is said to provide effectiveness similar to that of DEET. More and more product lines are beginning to contain this ingredient. Picaridin-based products are said to repel mosquitoes, flies, ticks, fleas and chiggers.
Natural topical repellents often use naturally occurring chemicals found in oils from eucalyptus, spearmint or peppermint, pennyroyal and tea trees. Oil of lemon eucalyptus is found naturally in eucalyptus leaves and twigs and has been a used as a bug repellent for decades. According to the EPA, like most plant oils, oil of lemon eucalyptus does not cause any of the adverse effects that may occur from using repellents with DEET. These products usually contain around 30 to 40 percent of the active ingredient.
Like oil of lemon eucalyptus, citronella oil has been used for more than 50 years as a repellent. It repels insects by masking the carbon dioxide on skin to which insects are drawn. Citronella oil is most commonly found in insect-repelling candles but also is the active ingredient in some products that you apply directly to skin, such as lotions, gels, sprays and towelettes. Because they evaporate quickly, topical citronella products often need to be reapplied more frequently than other products.
Always read the product label and follow manufacturer instructions before using a topical repellent and apply only the recommended amount of repellent to cover exposed skin. For extended periods of time, reapplication will be necessary. Pay special attention to the maximum amount of applications that you can use in a 24-hour period. When choosing a repellent, look to see that it suits your needs, providing protection for the desired length of time that matches your outdoor activities. Keep in mind that repellent results depend on other factors that affect protection duration, such as the amount that you perspire, water exposure for sustained periods, air temperature and your personal “attractiveness” to insects (some people attract more insects than others, due to body chemistry).
Always choose an EPA-registered product that provides protection duration on the product label.
When using topical repellents, only apply them to exposed skin and/or clothing but never on areas under clothing. Don't apply sprays directly near your eyes, nose or mouth. Never spray it directly on your face; apply it first to hands and then to your face. Don't use repellents on cuts, irritated skin or other wounds. When returning from the outdoors, wash your skin with soap and water to remove the repellent and launder your clothes.