Why mosquitoes bite some people moreWhy do mosquitoes bite some people more than others?

If you are the one who comes inside covered in bites while everyone else is fine, you are not imagining it. In a 2022 study at Rockefeller University, the most attractive volunteer drew about 100 times more mosquitoes than the least attractive one, and the mosquito magnets stayed magnets when they were retested over several years.

The cause is mostly not your blood, your diet, or bad luck. It is how your skin smells, and that comes from your skin's natural oils and the bacteria that live on it. You cannot change that much, which is why the reliable fix is the same for everyone: a good skin repellent.

A biting mosquito uses its senses in stages. From a distance, the carbon dioxide in your breath tells it a warm-blooded host is nearby and switches it into hunting mode. As it gets closer, it follows the odor coming off your skin. Up close, sight and body heat guide the landing. A 2022 University of Washington study found that once yellow fever mosquitoes have smelled carbon dioxide, they fly toward red, orange, black, and cyan, and toward the red-orange glow of human skin of every complexion, while ignoring green, blue, purple, and white.

Scent is the step that sorts people. In a 2023 Johns Hopkins study, researchers piped the air from six sleeping volunteers into a large outdoor flight cage in Zambia. Heat alone did not attract the mosquitoes, while body odor drew them in on its own, and one volunteer consistently drew the most landings.

Every person gives off a unique blend of odors from skin oil and the bacteria that break it down. The Rockefeller team found that the most attractive people had much higher levels of carboxylic acids on their skin, fatty acids that skin bacteria produce from skin oil. The Johns Hopkins study found the same pattern: its most attractive volunteer gave off more of these acids, while its least attractive volunteer gave off fewer of them and more eucalyptol, a compound found in some plants and foods.

The bacteria themselves matter. A 2011 Dutch study of 48 volunteers found that people with more bacteria on their skin, but fewer kinds of bacteria, were more attractive to the main African malaria mosquito. And because skin chemistry runs in families, so does attractiveness. In a 2015 UK study of 37 pairs of identical and non-identical twins, identical twins tended to be more alike in how attractive they were, and the researchers estimated that genes explain about 62 percent of the variation. The study was small, so treat that number as a rough guide.

Being a magnet is not one fixed trait. In a 2026 study, Florida International University researchers tested 119 volunteers against three common species in the US: the yellow fever mosquito, the Asian tiger mosquito, and the southern house mosquito. Each species ranked the same people differently, no one was highly attractive to all three, and being a favorite of one species barely predicted being a favorite of another.

Each species also keyed on different chemistry. The Asian tiger mosquito favored people who gave off more of certain compounds, including ketones, while the yellow fever and house mosquitoes favored people who lacked certain plant-type odor compounds. In practice, the person who gets eaten alive at a daytime barbecue, when tiger mosquitoes are out, may not be the same person who gets bitten on the porch after dark, when house mosquitoes take over.