National Geographic News
Picture of a hand covered in mosquitos

Mosquitoes avoid a hand treated with DEET (right).

Photograph by Greg Allen, USDA-ARS

Christine Dell'Amore

for National Geographic

Published September 17, 2013

Mosquitoes bugging you? There may be a new repellent on the horizon—and it's "so much better than anything else we've ever seen," its inventor says.

A few years ago, Ulrich Bernier was busy blending various chemicals together in the lab, hoping to figure out why the blood-sucking insects bite some people more than others. Mosquitoes home in on their targets by sniffing out various chemicals and bacteria on human skin.

When he created one blend with a group of chemicals that are very similar to ones found in low concentrations in our bodies, Bernier noticed that the bugs seemed to ignore it. (Read what happens inside you when a mosquito bites.)

These chemicals—which include the tongue twisters homopiperazine and 1-methylhomopiperazine, among others—seemed to have an incredibly robust ability to mask our scent from mosquitoes, said Bernier, a research chemist at the United States Department of Agriculture's Agricultural Research Service.

Next, Bernier and colleagues set up an experiment where people put their arms or hands inside a cage full of mosquitoes. The insects avoided the skin of the subjects when the chemical cocktail was released from a container inside the cage.

Bernier and colleagues created a formula of several chemicals for a repellent, which was approved by the U.S. Patent and Trademark Office in 2012.

"It's a pretty neat discovery because I don't think anyone else has shown chemicals this capable of blocking skin odors that are normally attractive to mosquitoes," said Bernier, who presented the research at the American Chemical Society meeting in Indianapolis last week.

Why do we need a new repellent?

Insect-borne diseases are prevalent and potentially dangerous. According to the U.S. Centers for Disease Control and Prevention, there are about 30,000 annual reported cases of Lyme disease, which is transmitted by ticks, and at least a thousand annual cases of mosquito-caused encephalitis—which includes West Nile virus—in the country. Bernier and colleagues' new repellent is also effective against other blood-sucking insects.

The most common insect repellent now in use is DEET, which is designed to be sprayed on the skin. However, there has been some concern about DEET and potential toxicity, and there's high demand for equally effective alternatives. (See "Mutant Mosquitoes Not Repelled by DEET.")

How does it work?

Bug repellents like DEET work by deterring mosquitoes that find the smell unappealing; the new formula actually makes you invisible to the insect.

Here's an analogy to explain the two: If you walk into a room and smell something bad and leave, that's how DEET works. But with the new repellent, it's as if you walk into a room and don't smell anything, Bernier said.

Bernier said it's unknown why insects can't smell the compounds.

How is the repellent applied?

Commercial availability is still far down the road—there needs to be more toxicology tests on the formula, as well as field tests, Bernier cautioned.

But he said that it could be used indoors or outdoors and would probably work best released into the air rather than applied to the skin. For example, the repellent could be emitted from a sealed canister that releases a vapor slowly into the air, creating a sort of protective bubble around your environment.

For instance, if you're sitting outside on a patio, you could install several canisters around the patio, he suggested.

Tell us: How do you avoid mosquitoes?

81 comments
Jarzinny Queen
Jarzinny Queen

what is the side effect of this chemical in human skin?

Haemish Kane
Haemish Kane

I have been traveling to India for over 30 years and staying for periods up to six months. I have also visited Nepal and Sri Lanka many times over the years. I have never taken Any malaria pills despite visiting regions like Orissa in India which is considered to be one of the most high risk areas for mosquitoes. I only use a mosquito net IF I feel there is a need for it. Usually, I have always used first choice, a mosquito liquid plug in which I Always leave on the whole day. If there are a lot of mosquitoes in the area I make sure my mosquito net is enclosed around the bed well before dusk. Always have a mosquito coil standby. Sometimes I might use a Deet spray, also a local Fly/ cockroach spray which I use under the beds  and room corners before I leave the room and go out for the day, but this is not necessary all the time. In the evening, and despite how hot it might be I Always wear jeans or Long trousers AND socks, a little spray of deet around this area and you will be prevented from being bitten while sitting in restaurants. I notice most tourist do not do this and in the evening come out in shorts and sandals very typical. It seems I might have been lucky just using Commonsense. However, I do stress I do stay in a high risk area!!

Chris Reymann
Chris Reymann

According to news week the number of lymes disease cases is actually 

300,000 annually that is a far cry from the 30,000 reported above.  

Jordan Hamilton
Jordan Hamilton

        This new repellent sounds very impressive. But is it safe if it comes in contact to people with sensitive skin? All of the chemicals that are in this mixture (even though they ward off blood-suckers) sound like they could be an allergic reaction waiting to happen. Living in the south, I know personally how irritating, as well as potentially dangerous, bites from certain insects can be. 

I usually use OFF Family Care Insect Repellent. After applying once to any skin that is exposed, it works wonderfully. Though the idea of mosquitoes ignoring your skin because your scent has been masked is interesting and impressive, I wonder if it is worth the risk. I am willing to try it, but probably not until it has been thoroughly tested and reviewed. 

Stewart Hines
Stewart Hines

CedarCide.

 Smells OK. 

Works on Humans and their pets.

晓 唐
晓 唐

That may be a good news for the person who is troubled by Mosquitoes.

Xira Arien
Xira Arien

The problem with DEET and lyme disease is that, for whatever reason, people don't put the stuff on and then get ticks (and mosquitoes and stuff).

You can't do much about the problem if people don't or can't afford to use the stuff.

http://llltexas.com <- my blog

Donna Watkins
Donna Watkins

I use Geranium Essential Oil in a carrier oil such as olive oil.  Then I simply rub it on my skin.  No toxicity and no mosquitoes!  Make sure you get 100% pure oils or it's not going to do you much good.  You can buy at wholesale prices at TheHerbsPlace.com.  Google and find more information on the effectiveness of this oil.  That's how I found out about it.  Been using it for years.  You can also put it in water and spray it around you or on your clothing.

Atmakuri Koteswara Rao
Atmakuri Koteswara Rao

under all circumstances the compounds of DEET should not expand the skin to close the pours of skin.

Nicole Clifford
Nicole Clifford

http://www.chemicaldictionary.org/dic/H/Homopiperazine_2207.html how do you get around the already known dangerous effects of homopiperazine?

Inhalation TOXIC; inhalation, ingestion, or skin contact with material may cause severe injury or death. Effects of contact or inhalation may be delayed.    Skin Contact with molten substance may cause severe burns to skin and eyes. See

Jim Corliss
Jim Corliss

In the South, we found red bugs, mosquitoes, no-see-ums all looking for a piece of your skin. After moving back to California...it is rare to see a  blood sucking bug! However, there is an abundance of lawyers!

Lyn Clarke
Lyn Clarke

What happened to the recent theory that "susceptible" persons had low cholesterol blood levels but high cholesterol laying on the skin?  The mosquitos are attracted to the cholesterol on the skin.  I use 100% DEET and still get bitten 10 x more than the next guy.  Invite me to your next party.

Sarah Sully
Sarah Sully

This could present a tremendous advance for those countries who's populations are stricken with malaria. 

joann garbutt
joann garbutt

I always get the bites, so I run into the house for salt, wet  your skin and shake salt try to rub it in and no more itching, leave the salt on for a while, the bite goes flat, try it doesn't hurt !

Raphael Tingang Anyie
Raphael Tingang Anyie

Will this new discovery be affecting the air we breath in? Would it be harmful for are respiratory system?

Haven Strange
Haven Strange

Ok, so what can we do to enhance our bodies chemistry to naturally produce these insect repellant chemicals when needed?

Artur Luiz Cunha Cunha
Artur Luiz Cunha Cunha

Espero que este produto chegue logo às prateleiras dos supermercados, pois aquí tem muitos mosquitos.

Daniela D.
Daniela D.

Wow, that sounds great! Scientists make progress. Good to see.
I wear long pants, socks and a sweatshirt while being outside. I use repellent on the exposed skin and I also believe lemon candles help. 
Once I got bitten, I try not to scratch (but honestly this is very hard). Sometimes I apply an anti-itching ointment or saliva and just wait until the itching pain goes away.

Bernice Vanover
Bernice Vanover

Garlic pills three times a day. It's two fold. It gives you energy and repels mosquitoes. :)

Trish Gussler
Trish Gussler

"For instance, if you're sitting outside on a patio, you could install several canisters around the patio, he suggested. "

I'm rarely sitting out on the patio. I'm walking or hiking and carrying a canister isn't going to work for me. 

Ick- more chemicals... Yes, I'm sure folks that are dying from mosquitoes would be okay with this, but there are better solutions on the horizon.

There is another project in the works, called Kite Patch. It's a patch you attach to your clothing that makes you invisible. Google it.

Charlie Stahl
Charlie Stahl

Like Mandie, I'm the one person in a crowd that will be bitten before anyone else. Sunday Morning did a show about how they are attracted to certain people more than others. Also, for the first time, there was a video made of what happens when they stick you with their proboscis (sp?). Pretty gross how they have something that can only be described as a very long and flexible appendage that is extended further into your skin as it probes for a capillary to puncture. Then is sucks so hard that the capillaries collapse. To keep them from biting, I use fresh, unused, Bounce dryer sheets. I rub it on my exposed skin and that pretty much takes care of them biting me unless I am sweating and then I may have to re-apply. I always carry a half dozen in my pocket when I'm outside after dusk.

Mandie M.
Mandie M.

This will be a lifesaver for someone like myself, who gets bitten 5x more than the people around me.  I can be outside for 10 minutes and get 5 bites, while my husband doesn't even see a mosquito.  It seems to have split among my children as well; 2 of them get bitten more than the other 2.  I think we all know that mosquitoes use various techniques to find prey, and breathing in chemicals may be bad for us, but how much worse could it be than DEET or picardin?  I use 25% DEET and STILL get bitten.  Very exciting findings.  Now if only they could find one to make me immune to freshly baked sugared goodies...

Timothy Steele
Timothy Steele

"Mosquitoes home in on their targets by sniffing out various chemicals and bacteria on human skin."

Ummm They follow CO2 emissions. WTF is this guy talking about.

Yasmeen Ashour
Yasmeen Ashour

I have secure mosquito netting on the windows and keep a spray should any come inside. If i am bitten I put toothpaste on it, it stops the itch quickly. If I am going out after dusk I spray lemon zest on exposed skin this seems to help.

Reena Chadee
Reena Chadee

I definitely need this, Im still recovering from Costa Rican mosquito bites! The bats were just not eating enough of those mosquitos out there! ha! 

Eugenie Tan
Eugenie Tan

New found substitute for Endocrine Disrupting DEET..

Haemish Kane
Haemish Kane

I am currently in India for six months having just visited Thailand, Cambodia, and Yes I am back in Orissa the high risk area..


Billy Corners
Billy Corners

@Xira Arien , the problem with deet is its a poison. You cant put it in young kids, and its only as useful as long as you can keep caking it on.

Wear long pants and sleeves, and pull your socks up over your pants to stop ticks from crawling up. Smelly people seem to attract more mosquitoes, maybe from sweat or bo, not sure why

Nicole Clifford
Nicole Clifford

regarding the other chemical mentioned in the article 1-methylhomopiperazine from the MSDS -

Potential health effects Inhalation Ingestion Skin Eyes May be harmful if inhaled. Material is extremely destructive to the tissue of the mucous membranes and upper respiratory tract. Harmful if swallowed. Causes burns. May be harmful if absorbed through skin. Causes skin burns. Causes eye burns.

Billy Corners
Billy Corners

@Jim Corliss , Horse flies, black flies, ticks , mosquities and fleas all over Maine. Black flies are so thick in spots in the deep woods that make  moose go running for the water for relief.

Billy Corners
Billy Corners

yup yup,malaria kills millions every year all over the globe. It could effect more of the US if things warm up a little also.

Christine Dell'Amore
Christine Dell'Amore

@Haven Strange That's a great question! I asked the scientist why our bodies produce such low levels of it if it's so beneficial, he said it's still a mystery. 

Charlie Wood
Charlie Wood

@Bernice Vanover : Actually, there is no science that supports that garlic repels mosquitoes. It does, however, repel vampires and potential romantic interests.

Cailen McCloskey
Cailen McCloskey

@Trish Gussler  You clearly don't understand what chemicals are. They aren't just "things that give you cancer" or things that make "frankenfood". Chemicals cure disease, chemicals made your drinking water safe, chemicals made your clothing. Chemicals made the nice, comfy world you live in. In this case, these are compounds isolated from your own body. Now, more research will tell us if it's safe to use like this, but what do you suggest, if not chemicals? I did look into the Kite Patch, it works the same way as this, except it's a sticky square instead of a canister. It's still giving off a chemical.

Christine Dell'Amore
Christine Dell'Amore

@Trish Gussler Since the chemicals are similar to/including ones found in our own bodies, they shouldn't be harmful. But yes I agree it would be good to have something portable to take with you.

Pat Serio
Pat Serio

@Charlie Stahl I have tried the dryer sheet approach myself, because I hike a lot. Even though it works, there is one problem, especially for those who are asthmatic -as myself - the odor makes it difficult to draw a breath without having an asthma attack. Just another reason why folks should not be out in public wearing fragrances ; ) Have you tried an unscented sheet? I'd be interest in knowing.

Christine Dell'Amore
Christine Dell'Amore

@Mandie M. Haha on the sugared goodies. I am like you, always getting bitten, which is part of the reason I wanted to write this article!

A J
A J

@Timothy Steele You are exactly not knowledgeable about what you are talking about. Although it is possible that mosquitoes "see" CO2, it's also possible that they are attracted to odors. It's established in mosquito science that certain people are attractors, and it has little to do with CO2, since we all exhale that.

And CO2 would not explain why they seem to have a particular preference for my feet and ankles.

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