Mozzies biting? Here’s how to choose a repellent (and how to use it for the best protection)
Mosquitoes are an inevitable part of the Australian summer. And this year we may be spending more time outdoors than usual with COVID.
Supermarkets and pharmacies are stocked with a wide variety of insect repellants, including aerosols, creams, gels, sprays, roll-ons, and wipes. There are even wristbands, fabric sprays, coils, sticks, plug-in devices and smartphone apps.
But not all products that are supposed to protect us from mosquito bites are created equal.
How do you choose and use a repellant to best protect you and your family from mosquito bites?
The main ingredients
Australian health authorities recommend using insect repellants that you apply directly to exposed skin to prevent mosquito bites and reduce the risk of mosquito-borne diseases.
All insect repellants sold in Australia must be registered with the Australian Pesticides and Veterinary Medicines Agency (APVMA), which reviews the safety and effectiveness of the products.
Despite the wide range of formulations available, only a small number of active ingredients are registered for use. Therefore, every insect repellent on store shelves in Australia contains at least one of these ingredients.
David Todd McCarty / Unsplash
Diethyltoumid (DEET) is one of the most widely used and recommended repellants in the world. It is effective in preventing mosquito bites and has been repeatedly shown to have minimal side effects when used as directed.
DEET formulations in Australia are available in a range of concentrations, from as little as 10% to high or tropical firmness products that can be as high as 80%.
Picaridin is a common ingredient in local mosquito repellent formulations and is effective in reducing mosquito bites. Like DEET, it has been classified as safe. Most of the formulations in Australia have concentrations less than 20%.
Lemon eucalyptus oil is increasingly common in mosquito repellants. The chemical p-menthane-3,8-diol comes from the leaves of the lemon-scented chewing gum Corymbia citriodora.
This ingredient is a by-product of the distillation process and is not an essential oil obtained from the leaves of the plant. This is important because this product is a much more effective repellant than essential oils (we’ll get into these alternatives shortly).
Formulations that contain lemon eucalyptus oil offer protection comparable to DEET-based repellants.
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The active ingredient in the repellent is listed on the packaging along with the concentration.
Any insect repellent containing these products should provide protection against biting mosquitos. But the stronger the formulation, the longer the protection lasts.
If you are only outside for a few hours, for example in the back yard, a highly concentrated formulation really isn’t necessary. But if you want to take a long bush walk or a fishing trip, choose a highly concentrated product (regardless of the active ingredient).
A / Prof Cameron Webb (NSW Health Pathology)
How you use it is also important
A dab here and there or spraying a repellent in the air around you like you would expect from a perfume doesn’t offer much protection.
These products must be applied thinly and evenly to all exposed skin areas. Imagine repellants that camouflage us from mosquitoes looking for blood.
While an aerosol or pump spray can allow application straight from the container, you will need to rub creams, roll-ons, and gels into your skin.
That doesn’t necessarily mean that one is better than the other. However, when choosing a formulation, consider which one you think is easiest to apply thoroughly.
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What about “natural” alternatives?
Some “natural” formulations containing tea tree oil and other herbal ingredients are APVMA registered. Products sold in local markets or online may not be registered.
In particular, products that contain plant-based repellants generally do not offer permanent protection against mosquito bites.
If you prefer products that contain tea tree oil or other herbal repellants, you need to be prepared to reapply much more often than with DEET, picaridin, or oil made from lemon eucalyptus formulations.
And avoid making your own insect repellants from essential oils. Without the controls associated with APVMA registered repellants, there may be a higher risk of adverse skin reactions.
A / Prof Cameron Webb (NSW Health Pathology)
Can anything help?
There is no evidence that mosquito-repellent wristbands or smartphone apps protect you from mosquito bites.
A range of candles, coils, sticks, plug-in and fan devices, and clothing treated with insecticides offer varying degrees of support in reducing mosquito bites. Unfortunately, none of them offer complete protection and are always best combined with topical mosquito repellants.
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Some people find so-called “chemical” repellants to be harmful to health. However, in most cases, they can be safely used on anyone over 12 months old. (For babies, it is best to provide physical protection, such as covering the stroller with a mosquito net.)
It is also often said that these traditional repellants are uncomfortable to use. Although the active ingredients have not changed significantly, the cosmetic ingredients of insect repellants have improved significantly in recent years.
To get through the summer, choose a repellent formulation registered with APVMA. Pick the one that is easiest to spread on the skin for full coverage. And always check the directions on the label.