Are you a 'mosquito magnet'? Your skin chemistry may be to blame

Some people seem to attract mosquitoes more than others, drawing the insects in with a combination of chemicals released from their skin.

Researchers at Rockefeller University in New York found that people with higher levels of certain acids on their skin can be up to 100 times more attractive to female Aedes aegypti mosquitoes, which can transmit diseases including dengue, chikungunya, yellow fever and Zika, reports The Washington Post.

The findings, published in the journal Cell, could help scientists develop products that mask or alter human odours, making it harder for mosquitoes to locate people and potentially reducing the spread of mosquito-borne diseases.

According to the World Health Organization, vector-borne diseases transmitted through mosquito bites and other infections cause more than 7,00,000 deaths each year.

Experts expect the number of cases to rise as global temperatures increase.

Jeff Riffell, a biology professor at the University of Washington and a mosquito expert who was not involved in the Rockefeller study, said, "A aegypti mosquitoes are typically found in tropical and subtropical climates but have expanded their range. The insects now breed year-round in places including Washington, DC, and much of California."

What makes someone a mosquito magnet?

Humans signal their presence to mosquitoes simply by breathing, according to Leslie Vosshall, chief scientific officer at the Howard Hughes Medical Institute and the lead researcher behind the study.

Female mosquitoes need blood to obtain the protein required to reproduce.

Vosshall compared a mosquito's blood meal to a large protein shake that allows the insect to produce eggs.

Scientists have also found that people can become more attractive to mosquitoes under certain circumstances, including pregnancy, after drinking alcohol and after using some types of soap.

These findings have prompted researchers to investigate the range of odours mosquitoes use to identify their next meal.

Vosshall's team wanted to understand why some people appeared to be more appealing to A aegypti than others.

Instead of exposing people to live mosquitoes, researchers collected their natural skin odours by having participants wear nylon stockings over their arms.

The stockings were then cut into small pieces and placed behind separate trap doors in a clear plastic box containing dozens of mosquitoes.

The researchers opened the traps and observed which sample the mosquitoes chose.

They conducted a round-robin-style tournament, recording how often mosquitoes were attracted to each sample.

One sample, identified as "subject 33," was particularly popular. According to Vosshall, the sample won 100 rounds and remained undefeated.

The study found that people like subject 33 had higher levels of compounds known as carboxylic acids on their skin. These individuals were more likely to be "mosquito magnets."

Skin bacteria may play a role

All humans produce carboxylic acids through sebum, the waxy substance that coats the skin.

Millions of beneficial microorganisms living on the skin feed on sebum and produce carboxylic acids as by-products.

When present in large amounts, these acids can create odours that resemble cheese or smelly feet.

Researchers believe these odours may help female mosquitoes locate humans.

The stockings used in the experiment did not actually smell of sweat, Vosshall said.

Mosquitoes are highly sensitive to human odours, and perfume or cologne does not necessarily mask them.

The experiment lasted three years, and participants who attracted mosquitoes continued to do so over time, regardless of what they had eaten or whether they had changed their shampoo.

"If you're a mosquito magnet today," Vosshall said, "you will be a mosquito magnet three years from now."

The study did not establish why some people have higher levels of carboxylic acids than others.

Vosshall suggested that differences in the skin microbiome could be partly responsible, as every person has a unique community of bacteria living on their skin.

LJ Zwiebel, a professor of biological sciences at Vanderbilt University who was not involved in the research, said carboxylic acids are clearly linked to mosquito attraction, but there is no single compound responsible for drawing mosquitoes in.

Instead, he described mosquito attraction as a "cocktail" of different signals.

Mosquitoes use multiple sensory cues to locate people, with carboxylic acids being one important component.

Research published in Nature in 2024 also found that mosquitoes use infrared radiation to help locate humans.

How to make yourself less attractive to mosquitoes

For people looking to avoid mosquito bites, Zwiebel recommends showering to reduce the compounds that accumulate on the skin, particularly around the feet, which can produce distinctive odours.

People can also take steps around their homes to reduce mosquito exposure, including choosing outdoor plants carefully and using effective repellents and mosquito-control devices.

Vosshall believes future research could focus on manipulating the odours produced by the skin and the bacteria living on it.

Scientists may eventually be able to develop probiotic skin creams that interfere with or reduce certain bacterial by-products, making people less attractive to mosquitoes.

Understanding what makes some people "mosquito magnets," she said, could ultimately help researchers find ways to prevent mosquitoes from targeting them.