Insect Repellents - Topic Overview
You can lower your chance of being bitten by an insect or
spiderlike animal (arachnid) by using insect repellents. Mosquitoes, biting
flies, and ticks can cause annoying bites and sometimes a serious disease.
Mosquito bites can spread infections such as
West Nile virus, a virus that causes swelling of the
brain (encephalitis), and
malaria in some parts of the world. Tick bites can cause serious diseases such as
Lyme disease and
Rocky Mountain spotted fever. Bites from biting flies
are painful and may cause a
You can buy many
different kinds of insect repellents. Some work better than others. DEET
provides the longest-lasting protection against mosquito bites.1
If you have a question or concern
about the use of insect repellents, or if you are pregnant or nursing, talk with your doctor.
Products that work the best
(N,N-diethyl-3-meta-toluamide) is the most effective insect repellent.
- A solution of 23.8%
DEET provides about 5 hours of protection from mosquitoes.1 DEET is available in
varying strengths up to 100%. Research shows that strengths greater than 50% do
not provide substantially higher protection. Unless you are in areas with a large
number of mosquitoes, repellents with 10% to 24% DEET should keep most
mosquitoes away from your skin.
- Concerns have been raised about
safety, because DEET is applied to the skin. Studies over the past 40 years haven't shown that DEET causes cancer or other illnesses.
- Experts disagree about
the safest concentration of DEET to use on children. No serious illness has
been linked to the use of DEET in children when used according to the product
recommendations. The American Academy of Pediatrics (AAP) and other experts
suggest that it is safe to apply DEET in concentrations of 10% to 30% DEET to
children older than age 2 months. When applying DEET to children 2 months to 24 months of age:
- Use only when there is a high risk of insect bites.
- Use repellents with the lowest concentration of DEET available (usually 10% to 30%).
- As with all insect repellents, use DEET sparingly, and never apply to the hands or near the eyes.
- Apply no more than 1 time a day, and avoid prolonged use.
- When applying DEET to children 2 years to 12 years of age:
- Use repellents with the lowest concentration of DEET available (10% to 30%).
- Apply no more than 3 times a day, and avoid prolonged use.
- If you are pregnant or
breast-feeding and have concerns about the use of DEET, talk with your doctor.
There is no evidence that the use of DEET by pregnant or lactating women poses
a health hazard to developing babies or children who are breast-feeding.
- Do not use DEET products that are combined with sunscreen.
Sunscreen needs to be applied more often than DEET.
- DEET reduces
how well sunscreen works by one-third.2 If you need to use sunscreen and DEET at
the same time, put on sunscreen first and wait 20 minutes before applying DEET.
Do not use DEET on skin that will be covered by clothing.
- DEET should also be used carefully on clothing. DEET may damage
some synthetic fabrics as well as plastic watch crystals and eyeglass