Repelling Insects: Choose the Right Repellent for You

So how do we protect ourselves—insect repellent—but which one?? What do we look for? How do we compare?

Teresa Hunsaker with Utah State University Extension Service’s in Weber County shares tips on bug repellants and how to choose the best one for you and your family.

The first thing that is important to know is that repellents do not kill insects, but rather keep certain species away from the treated areas—it repels them. Most repellents are volatile, and after they are applied to the skin or clothing, the released vapor discourage insects from approaching because they do not like the smell.

Secondly, there are ingredients in repellents that, as a consumer, you want to understand and feel OK about using. Insect repellents recommended by the Centers for Disease Control and Prevention (CDC) include those containing “DEET”, as well as products containing “picaridin” and “oil of lemon eucalyptus”, which have also been shown to offer long lasting protection against mosquito bites. Picaridin repellents with seven percent active ingredient provide longer lasting protection, whereas repellents with 30 percent oil of lemon eucalyptus as the active ingredient provide protection equal to a low concentration DEET product.

The EPA has recently (2007) released a new compound safe for use in insect repellants. Its trade name is BioUD™. Research shows BioUD™ outperforms DEET and the eucalyptus compound found in Off Botanicals in testing against mosquitoes at six hours post application. In fact, BioUD™ demonstrates 100 percent repellency against mosquitoes up to three hours after application and 99 percent repellent up to 4.5 hours in forest and marsh conditions. Its use is recommended by the American Pediatrics Academy. Made with plant-based ingredients including soybean oil and geranium oil, Bite Blocker outperforms many other natural insect repellents in comparison tests, though it is not consistently effective. Its protection time (90 minutes to two hours) is not as long as another highly rated natural repellent, Repel Lemon Eucalyptus, which has a protection time of about four to six hours. Unlike Repel, however, BioUD is suitable for children as young as 2 months old. Reviews report that it is also effective against black flies. It is available in a spray known as Bite Blocker and is found in most Wal-Marts and some health food stores-namely, Wild Oats.

Oil of lemon eucalyptus is not currently recommended for children under 3 years of age. Picaridin can be used for children of all ages. Parents and other persons should read container labels thoroughly before applying any mosquito repellents to young children. Avoid getting the repellent on children’s hands or in their eyes or mouths.

There are also other “botanical” repellents that have also been approved and been found to be effective for warding off mosquitoes, fleas, and ticks. They contain any number of plant based essential oils.

If choosing a repellent containing DEET (N,N,diethyl-m-toluamide) select a product containing the amount of DEET to match the time you will be spending outdoors. Repellents containing 25 percent DEET protect for an average of five hours per application, while repellents containing 20 percent DEET protect for almost four hours. Repellents containing 6-7 percent DEET protect for almost two hours and repellents containing 4.75 percent DEET protect for approximately one-and-a-half hours. NOTE: A higher concentration of DEET does not equate to better repelling of mosquitoes—just longer lasting. So, the higher the percentage of DEET—the longer their effectiveness while outside. Body temperature, sweating, and water activity also affect the ability of the repellent to maintain its effectiveness—so it may be necessary to apply more frequently.

Consumer Report has listed a few of their top picks, as far as brands and effectiveness. Here are four:

Cutter Advanced—Best insect repellent overall.


• Long-lasting protection (which means higher concentration of DEET)

• Safe for kids as young as 2 months

• Odorless

• Non-stickiness

• Doesn’t damage plastics


• Eye irritation

• Inconsistent effectiveness

3M Ultrathon Insect Repellent—DEET repellent for long periods or extreme conditions


• Protects up to five hours

• Special DEET formula

• Water resistant

• Works against ticks and biting flies


• Not for use with babies

• Can damage plastic and paint

• Needs to be washed off after returning indoors

• Expensive

Repel Lemon Eucalyptus—Best natural mosquito repellent


• Long-lasting protection

• Won’t damage plastics or synthetics

• Plant-based ingredients


• Inconsistent effectiveness

• Limited usage (twice a day)

• Can stain leather

• Not for use with children under 3

Bite Blocker—Safest insect repellent for kids


• Safe for children and pregnant women

• Plant-based ingredients

• Repels black flies, mosquitoes and ticks


• Variable protection time

• Scent

• Sticky

For those interested in considering botanical formulas using essential oils in their insect repellents, the following have been found to be very effective: (sweet) bay, catnip, cedar wood, cinnamon, citronella oil, clove, eucalyptus, fennel, geranium, lavender, peppermint, rosemary and thyme.

To make your own insect repellent using some of these essential oils, consider the following:

1. Choose almond or sesame oil as your “carrier oil” or base oil—what the essential oils are mixed with because they would be way to strong on the skin otherwise. Buy only almond or sesame oil that is specifically designed to be used for massage. They have been refined and prepared for use on the skin. Sesame oil has the added benefit of being a natural sunscreen. You can get them at health food stores and online.

2. Blend the insect repellent oil by mixing one to three essential oils (listed previously)with the “carrier” oil. Measure the almond or sesame oil into the plastic bottle, then add three to six drops of essential oil per teaspoon of “carrier” oil. Shake well.

3. Rub the oil on all exposed parts of your body and gently massage in. Make sure you cover yourself well–and don’t forget your feet.

Here is another homemade recipe:

Homemade Mosquito Repellent

1/3 cup apple-cider vinegar

1/3 cup witch hazel

5 drops citronella oil

Small spray bottle

Pour all ingredients in spray bottle. Shake well each time before you spray. The vinegar smell will go away quickly…as will the mosquitoes.

In summary:

• Check to see if the repellent contains any of the above ingredients. Many scientists believe that repellents with one or more of these three are the most effective.

• Select the appropriate concentration of DEET, or other active ingredient, for you. Consider how long you’re going to be outdoors. A repellent with a higher concentration of DEET lasts longer outside, while a smaller concentration of DEET, is adequate for a short amount of time spent outdoors. Typically as the concentration goes up, so does the price.

• Consider your activity and select your form of repellent. If you want to apply the repellent to your clothing, a lotion will not work. An aerosol or a pump spray would be better. Maybe you don’t want to smell like repellent; choose a scented option. If you’re going to be in the sun, a repellent combined with sunscreen would be best. Keep your activity in mind when making your decision.

Final Points:

1. No insect repellent should ever be applied for prolonged periods’ of time or used in excessive amounts.

2. Insect repellents should never be applied to cuts or to broken skin.

3. The higher the concentration of DEET, the higher the number of other bugs the repellent is effective for—fleas, ticks, and a broader variety of mosquitoes.

If you have any questions, call the Family and Consumer Science Education Department at the Weber County USU Extension office at (801) 399-8203 or online at

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