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New research finds that mosquitoes are more attracted to certain types of soap, increasing your risk for itchy bites. stefanamer/Getty Images
  • A new study has found that washing with different soaps may change how mosquitoes perceive you.
  • Washing with soap was shown to alter a person’s odor profile, making them more or less attractive to mosquitoes.
  • Experts say floral scents in particular may make you more attractive to mosquitoes
  • To make yourself less attractive to mosquitoes, you can use products containing DEET, picaridin, citronella, lemon, and eucalyptus.

Have you ever spent a summer evening outside with friends only to find, hours later, that you’re covered in mosquito bites? Meanwhile, the people you were hanging out with have none.

New research suggests that the soap you wash with could be to blame.

A study published in the journal iScience found that washing with some soaps attracted mosquitoes, while other soaps were repellent. These effects varied between different people as a result of interactions between the soaps and each person’s unique odor profile.

The researchers reason that soaps may change how mosquitoes perceive and discriminate between us as possible blood donors. They noted in a press release that mosquitoes also feast on plant-nectar and “dousing ourselves with plant-derived or plant-mimicking scents could potentially confuse their decision-making.”

To conduct the study, the research team characterized the chemical odors of four volunteers when unwashed and after they’d washed with four different brands of soap: Dial, Dove, Native, and Simple Truth.

The researchers found that each volunteer emitted their own unique odor profile – some of which were more attractive to mosquitoes than others. They discovered that soap washing “significantly” changed the volunteer’s odor profiles.

Commenting on the results, co-author of the study Chloé Lahondère said in a press release that, “soaps drastically change the way we smell, not only by adding chemicals but also by causing variations in the emission of compounds that we are already naturally producing.”

Louisa Messenger, a UNLV School of Public Health researcher who specializes in the control of tropical infectious diseases transmitted by insects, says she’s not at all surprised by these findings.

“These results are consistent with several previous studies, showing that the level of mosquito attraction varies substantially between individuals,” she notes.

While the results are what she would expect, there’s still so much we don’t know about why some people are more attractive to mosquitoes than others, or why soaps appear to affect this. It’s complex and highly individual.

Each person’s body odor is believed to play a huge role in their level of attractiveness to mosquitoes, and washing with different soaps appears to alter each person’s unique scent.

“It’s well known that microbial composition on the skin plays a key role in the production of human body odor. The soaps tested in the study are presumably having a dual effect of altering the skin microbiota as well as the attractant or repellent chemicals in the specific soaps tested,” says Messenger.

David Price, associate certified entomologist for Mosquito Joe, holds a similar view.

“I would speculate that most people are more attractive to mosquitoes after washing with certain soaps than they are unwashed, because of the combination of ingredients, the person’s reaction to those ingredients, and the way they are absorbed into the skin,” he surmises.

“Genetically, the female mosquito is designed to feed on blood to fertilize eggs, and inherently, certain molecules and odorants in soaps and body washes will trigger a different response,” he adds.

While the results of this study could help you make more mindful choices in the personal hygiene aisle, both experts agree that more research is needed.

“Mosquitoes are attracted to carboxylic acid and lactic acid, both of which are present in the human body, so it would be interesting to see if a soap or lotion could be developed to neutralize these acids and reduce their attractiveness,” says Price.

“Therefore, the next steps as far as research is concerned would be to understand what the neutralizer would be and how it could be absorbed enough into the skin without a reaction.”

Meanwhile, Messenger believes the main objective of future studies should be to develop better repellents to prevent mosquito bites or attractants that can be deployed in mosquito traps.

You might be wondering what soaps you should wash with to repel mosquitoes and which could make you more attractive to them. Messenger says mosquitoes like floral scents “due to their plant nectar feeding behavior” so it may be best to avoid soaps and body washes containing these.

Meanwhile, some of the scents which repel mosquitoes are the ones used in commercially available insect repellents like DEET, picaridin, citronella, lemon, eucalyptus, and other pyrethroid insecticides.

Price also recommends soaps that contain neem oil or the fatty acid of coconut oil.

“These have been scientifically proven to repel mosquitoes in various countries,” he explains.

Still, Messenger stresses that soaps aren’t the best way to repel mosquitoes.

“Stick to the proven repellent insecticides that can provide hours of protection and are approved by the US Environment Protection Agency, such as 25% DEET, picaridin, and citronella,” she advises.

These insecticides can be purchased as sprays, candles, and wipes.

Soaps and proven repellents aside, there are loads of ways you can repel mosquitoes. Messenger says simple measures are the best way to prevent bites.

“Mosquitoes need standing water for their larvae, so make sure to remove any standing water from around your home and workplace,” she advises. “You should cover items that can contain water such as old tires, plastic buckets, and plant pots, and make sure that swimming pools are kept treated.”

In addition, Messenger says wearing long sleeves and trousers can also help to a degree, while Price recommends wearing light-colored clothing as mosquitoes are attracted to darker shades.

There’s still so much we don’t know about what makes some people so attractive to mosquitoes. Hopefully, this new research will go some way to helping you avoid those itchy bites.