Your breath
The primary way mosquitoes find their targets from a distance is by detecting the carbon dioxide (CO2) we exhale. They use highly sensitive receptors to follow these plumes of gas back to their source. Consequently, people who produce more CO2 are more likely to be found. This includes larger individuals, people who are exercising, and pregnant women, who exhale about 21% more CO2 than non-pregnant individuals, according to the American Mosquito Control Association.
Body odor
Once a mosquito gets closer, a more sophisticated set of cues comes into play, primarily centered on body odor. This "odor profile" is determined by hundreds of chemical compounds on our skin, many of which are produced when our skin’s unique microbiome—the community of bacteria living on us—breaks down substances in our sweat. It’s not the sweat itself but this bacterial process that creates the scent.
A groundbreaking 2022 study published in the journal Cell identified a key culprit: carboxylic acids. These greasy molecules, part of the skin's natural moisturizing layer, are particularly irresistible to mosquitoes. Researchers found that individuals with high levels of these acids on their skin were consistently "mosquito magnets." This trait remained stable over time, suggesting a strong genetic link to our personal scent profile. This explains why your attractiveness to mosquitoes likely doesn't change much throughout your life.
Blood type
Other factors also contribute to your appeal. Studies have shown that mosquitoes may have a preference for certain blood types. Research published in the Journal of Medical Entomology found that in a controlled setting, mosquitoes landed on people with Type O blood nearly twice as often as on those with Type A.
Body temperature
Heat and metabolism also play a role. Mosquitoes are drawn to warmth, so a higher body temperature, whether from genetics or recent physical activity, can make you a more appealing target. Furthermore, consuming alcohol can increase your attractiveness. A small study showed that people who drank just one bottle of beer were significantly more attractive to mosquitoes, though the exact reason—whether it’s increased body heat or a change in skin chemicals—is still being investigated.
Your clothes
Finally, even your choice of clothing matters. Mosquitoes are visual hunters, especially in the late afternoon. Dark colors like black, navy blue, and red stand out against the horizon, making you an easier target to spot.
So, if you feel victimized by these tiny pests, it's not your fault. It's a combination of the CO2 you breathe, the unique chemical signature you emit, your body heat, and perhaps even your blood type—a complex profile that makes you, unfortunately, irresistible.
Sources of Information:
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De Obaldia, M. et al. (2022). "Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels." Cell, 185(22), 4099-4115.e15.
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American Mosquito Control Association. "Why am I a mosquito magnet?" AMCA.org.
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Shirai, Y., Funada, H., Takizawa, H., Seki, T., Morohashi, M., & Kamimura, K. (2004). "Landing preference of Aedes albopictus (Diptera: Culicidae) on human skin among ABO blood groups, secretors or nonsecretors, and ABH antigens." Journal of Medical Entomology, 41(4), 796-799.
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Shibuya, T., Tsuchiya, T., Hori, M., & Tsuruoka, H. (2002). "Ethanol ingestion increases mosquito attraction." Journal of the American Mosquito Control Association, 18(2), 91-96.
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Day, J. F. (2021). "Mosquitoes and Their Control." University of Florida, IFAS Extension, Publication #ENY-645.
