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Are you using mosquito repellent incorrectly?

Monday 27 November 2017

A woman wearing denim shorts sprays mosquito repellent across her legs.
Did you know that mozzies can locate patches of skin that you missed when putting on repellent?

Picture this: it’s a warm summer evening in Queensland and you’ve been invited to a barbeque. You grab your esky, some bread rolls and snags, and a can of mozzie repellent.

You arrive at the party and duck outside with the repellent. Do you:

  1. Spray a fine mist over the tops of your arms and legs, figure you’re done for the night and chuck the container back in your bag?
  2. Spray everywhere with a double coat, including your hair and up your shirt, because you know mosquitoes are wily and you can’t be too careful?
  3. Spray the repellent into the air and walk through the cloud like Beyoncé emerging through a haze of dry ice to greet her adoring fans, then return to rock the party?

Nothing’s more annoying than an itchy mosquito bite, especially when you did the right thing and used repellent. However it turns out that mosquito repellent application is a fine art, and none of the above techniques are the best way to prevent being bitten by mozzies (yes, we tricked you with an unwinnable quiz).

Read on to find out how mosquito repellent works and how to apply it to make sure you’ll be properly protected.

On stage, Beyonce sings in front of two back up dancers.

What is mosquito repellent?

There are different types of mosquito repellent available and different ways you can use them. From sprays and roll-ons to ‘wearable devices’, the one thing they all have in common is their aim to make mosquitoes leave you alone.

Repellents can either be made of synthetic chemicals or botanically derived products. Synthetic chemical repellents will usually contain chemicals like diethyltoluamide, better known as DEET, Picaridin, or PMD. The stronger the chemical concentration in these repellents, the longer the repellent will be effective.

Botanically derived repellents use plant extracts like eucalyptus, citronella, melaleuca, peppermint and leptospermum (commonly called tea tree) to repel mozzies. They can use one or a combination of these ingredients in concentrations less than 10%, and repel mosquitoes for a limited amount of time.

Wearable devices might include patches or wrist bands that aim to repel mosquitoes and often have botanical products in or on them. These products don’t offer effective protection from mosquitoes.

How does mosquito repellent work?

Female mosquitoes feed on human blood to get the protein needed to make eggs. They detect carbon dioxide and the ‘smell’ of our skin when searching for their next blood feed.

Repellents work to mask these triggers, making mosquitoes look elsewhere for a feed. A mosquito might even land on a person with properly applied repellent but not feed, because they’re not picking up the right cues.

A little girl sits on a bed, her legs covered in red mosquito bites.

How to apply mosquito repellent properly

The most important thing to know is that mosquito repellent will only work if you apply it to all areas of exposed skin. A few dabs here and there will not protect you: mosquitoes can find and feed on patches of uncovered skin.

To apply repellent properly:

  • spray or roll over all areas of exposed skin
  • make sure you apply an even coat – it might help to apply pump or roll-on formulas to your hands and then spread it on your skin
  • reapply regularly as directed on instructions on the product packaging.

The type of repellent you use (synthetic chemical or botanical) and the concentration of the ingredients will determine how effective the protection is and for how long. For example, repellent with a DEET concentration of less than 10% will protect you for about 2 hours, while a 20-40% concentration will protect you for 4-6 hours. Read the packaging to find out how often you should reapply your repellent.

Putting on large amounts of repellent at a time isn’t any more effective than applying one even coat and it doesn’t make the repellent last any longer. Save your money and focus on proper application rather than drenching yourself.

You don’t need to apply repellent underneath clothing. This can increase the amount of repellent that absorbs into your skin. Wearing loose, light coloured clothing can reduce your risk of getting bitten through your clothes.

Some repellents are not suitable for children under 3 months of age. Remember to check the manufactures’ recommendations. Do not let young children apply their own repellent. The repellent should be applied to the hands of the carer first, then to the exposed skin of the child in an even fashion.

Why use repellent?

Mosquito bites can be itchy and annoying, but there are other important reasons to use repellent.

Mosquitoes in Queensland can carry and transmit a number of diseases, cases of which can range from mild to severe and sometimes fatal. Protecting yourself against mosquitoes can help prevent you from contracting mosquito borne diseases and stop the spread of these diseases. A full list of mosquito borne diseases that Queensland has an established surveillance system for can be found here.

A close up of a mosquito, biting a person's arm.

How do I know if my repellent is safe to use?

Some people wonder about the safety of using synthetic chemical repellents containing ingredients like DEET on their skin.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) regulate products like insect repellent, assessing them in relation to human and environmental safety and ensuring their packaging displays the name and concentration of active ingredients. You can search to make sure your repellent is registered with APVMA using the Public Chemical Registration Information System Search.

The safety of any repellent products depends on them being used correctly. It’s important to remember that adverse reactions can also arise from botanically derived products. Always read the label on your product and follow the directions for use exactly. Pay particular attention to instructions about applying the repellent to your face, application for children, reapplication and first aid directions if you experience an adverse reaction.

Last updated: 11 December 2017