If you've ever wondered why mosquitoes feast on you while leaving your friend alone, science finally has some answers — and no, it's not about your blood type.

Researchers are making progress in understanding the complex chemical cocktail that turns some humans into mosquito magnets. Frederic Simard, a medical entomologist at France's Institute of Research for Development, told AFP that "it's not a misconception — mosquitoes are attracted to some people more than others." But he added that "we aren't all magnets all the time."

Female mosquitoes — the only ones that bite — use finely-tuned receptors to detect signals from humans. Carbon dioxide is the first thing that draws them from dozens of metres away, according to Swedish scientist Rickard Ignell. Within about 10 metres, they start picking up body odour. As they get closer, body temperature and humidity seal the deal.

Popular theories about blood type preference? Skin, eye, or hair colour also don't matter.

What does matter is odour. Humans release between 300 and 1,000 different odorous compounds, produced by the bacteria living on our skin. Scientists are only beginning to understand which ones attract mosquitoes.

For a recent study, Ignell's team released Aedes aegypti mosquitoes — the kind that spread yellow fever and dengue — on 42 women in a lab. They identified 27 odorous compounds that mosquitoes detect out of the possible 1,000. The woman mosquitoes most liked to bite, including pregnant women in their second trimester, produced large amounts of a compound called 1-octen-3-ol, also known as mushroom alcohol. Even a small increase made a difference, Ignell said, calling it a surprise.

Drinking beer also makes you more attractive to mosquitoes. Studies show it raises body temperature, increases exhaled CO2, and changes skin odour. In Burkina Faso, volunteers drank beer and then water on separate days. The Anopheles mosquito — which spreads malaria — preferred the scent of beer drinkers. A 2023 study in the Netherlands found that volunteers who'd had beer in the previous 24 hours were 1.35 times more attractive to female Anopheles mosquitoes.

Climate change is making this research more urgent. The tiger mosquito, a vector for chikungunya virus, is spreading into new areas. Last year, chikungunya reached France's Alsace region for the first time. "This risk is affecting more and more people," Simard said.

So what can you do? Simard advises loose-fitting clothing that covers your skin, mosquito nets, and repellent. He also suggests eating light meals and going easy on the alcohol.

  • Female mosquitoes are the only ones that bite
  • Humans release 300–1,000 odorous compounds from skin bacteria
  • Mosquitoes detect 27 of these compounds, including mushroom alcohol (1-octen-3-ol)
  • Beer drinkers are 1.35 times more attractive to Anopheles mosquitoes
  • Chikungunya reached France's Alsace region for the first time in 2025