Why mosquitoes bite some people more often

Paris – 04/08/2026: After a summer evening, some people are covered in mosquito bites while others are almost completely spared. This is not purely a matter of chance. A Franceinfo program broadcast on Tuesday examines which physical characteristics attract mosquitoes and how to protect yourself effectively. According to the French health authority Anses, the insects use several signals: exhaled air, skin odor and body temperature.

Carbon dioxide plays an important role. People emit it when breathing, and mosquitoes can detect it and use it to search for a host. There are also substances produced by bacteria on the skin that shape an individual’s body odor. Genetic factors can also influence how attractive a person is to mosquitoes. However, no single characteristic is decisive; what matters is the combination of different stimuli.

Physical condition can amplify these signals. Pregnant women, people with a fever and people who have consumed alcohol may be preferred hosts because body heat, breathing or skin odor can change. The idea that some people generally have “sweeter blood,” on the other hand, is one of the common explanations without solid evidence.

Clothing also affects the risk of being bitten. According to Anses, mosquitoes react more strongly to dark colors. Light-colored, loose-fitting clothing that covers as much of the body as possible makes it harder for them to reach the skin. This is particularly relevant in view of the Asian tiger mosquito, Aedes albopictus, which is widespread in France. It can be recognized by its black-and-white markings and, unlike many native species, is mainly active during the day, especially in the morning and late afternoon. Only females need blood to develop their eggs.

For protection, the French health insurance service Ameli recommends combining several measures. Approved repellents should only be applied to exposed, healthy skin. Age, pregnancy and the manufacturer’s instructions should be taken into account when choosing a product. Creams or lotions can be applied more precisely than sprays and reduce the risk of inhaling or swallowing the active ingredient. The eyes, mouth, and irritated or injured skin must be avoided.

Anyone also using sun protection should apply sunscreen first and allow it to absorb for around 20 minutes. The mosquito repellent should only be applied afterwards. After swimming or heavy sweating, another application may be necessary, provided that the maximum daily amount stated on the packaging is not exceeded. The most reliable protection therefore comes not from a supposed secret weapon, but from combining suitable clothing, approved repellent and correct application.