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The amount of active ingredient per volume or weight is not an indication of toxicity of the product, but rather an indication of the length of time for which the product provides useful protection – a product with 80% DEET is no more effective than a product with 10% DEET so long as the product with 10% DEET is applied with sufficient frequency (perhaps every two hours against perhaps 14 hours for a product containing 80% DEET). It is highly unlikely that 10 hours of continuous protection will be required under any circumstance that does not permit the application of the repellent in subsequent occasions.  It may in fact be more beneficial to use product with lower concentrations of active ingredient, such as Nopikex at 22% or 23.8% which would require application after approximately eight hour of exposure, than to use a product with 80% DEET or even 100% DEET which may provide protection for up to 10 hours.  The primary reason for this is psychological in that it is better to be fully aware of the constant threat of vector-borne diseases in endemic areas (something application of a mosquito repellent every few hours will provide) than it is to use a product that provides “all day” protection which might lead a person to overlook the need to reapply it after such a lengthy period of time. Irrespective of the percentage of active ingredient per volume/weight or the age of the person using the repellent, any repellent applied topically should:

1. Never be applied to areas of the skin which will be subsequently covered – e.g. do not put it on your arms, then put on a long sleeved shirt.
2. Never be applied to the lips, ocular areas (close to the eyes), inside nasal cavities or around the genital areas of the body.
3. Be washed off completely within a 24 hour period, then reapplied if necessary.
4. Applied with care to children’s hands as they will likely have a tendency to rub their eyes or stick their fingers in their mouths without full awareness of the active ingredient in the repellant – while neither of these actions are likely to cause serious harm, they will surely cause considerable discomfort.