
Health Canada announced a decision to ban repellents
with higher than 30% concentrations of DEET from stores.
This took effect in Dec. 2004.
As well, a study in the New England Journal of Medicine was published indicating that DEET repellents give the best protection from mosquitoes.
Avoiding insect bites can be difficult, but before you use an insect repellent, try these methods:
If these fundamental precautionary measures are not enough, repellents are the next step.
DEET (N,N-diethyl-m-toluamide) is the most effective and widely used chemical in insect repellents. It is a toxin, so you should choose the lowest DEET concentration that you need.
In most situations, less than 30% DEET will adequately protect an adult.
When selecting a DEET product, remember that lower DEET concentrations are as good as higher concentration products, but for a shorter time period.
As a rule of thumb, products with 5-6% DEET are good for 2 hours, 7-10% for 3 hours, 11-14% for 4 hours, 15-21% for 5 hours, and 22-30% for 6 hours.
Natural Insect Repellent
Natural oil-based repellents often contain only plant-based ingredients such as citronella, and are not as effective as chemical-based repellents. However, natural oil-based repellents are safer, making them a good choice for children, those who suffer from skin irritations, and those who use insect repellent for extended periods of time. Note that some people are allergic to essential oils, so test a patch of essential-oil-based repellent on your skin before using it.
Keep in mind that natural oil-based insect repellents need to be applied frequently in order to remain effective. Products that contain citronella may last up to twenty minutes, while eucalyptus oil products last an average of two hours.
When you use DEET repellents, be aware that there are some dangerous side effects that have been associated with improper use, particularly with children being exposed to high concentrations.
DEET Repellent Use Guidelines for Everyone:
More DEET Product Use Guidelines for Children:
There are some additional things that you should know about repellents.
These files are from good sources. (in PDF format)
Article from The New England Journal of Medicine
Health Canada Pest Management Publication
Health Canada Safety Tips brochure