Why do mosquitoes bite some people more than others?

Mosquitoes locate hosts through a layered system: carbon dioxide from your breath draws them from a distance, then body heat, moisture, and skin odor guide them in close. The odor component is the biggest differentiator between people, and recent research points specifically to carboxylic acids produced by skin bacteria, with a 2022 Rockefeller study finding that people highly attractive to mosquitoes had substantially elevated levels of these compounds and that the ranking stayed stable over years, suggesting it is a durable individual trait rather than something you can wash off or eat your way out of.

Other factors have real but smaller support. Studies have found type O blood attracting more bites than type A in some experiments, pregnant people and larger bodies exhaling more carbon dioxide, exercise raising both heat and lactic acid, and drinking beer measurably increasing attractiveness for reasons still unclear. Dark clothing makes you more visually conspicuous. What does not hold up is the folklore about sweet blood, and popular avoidance strategies like eating garlic, taking vitamin B, or using ultrasonic repellent devices have consistently failed in testing. What works is EPA-registered repellent, DEET, picaridin, or oil of lemon eucalyptus, plus covering skin and eliminating standing water where they breed, which matters more than personal chemistry since mosquitoes remain the deadliest animal to humans by a wide margin through disease transmission.