Why mosquitoes bite some people more than others, scientists finally have answers

• Scientists say mosquitoes really are more attracted to some people than others, and your body chemistry plays the biggest role.

• Carbon dioxide, body odour, and more can make you a more attractive target.

• Experts recommend using insect repellent, sleeping under mosquito nets and wearing loose, long clothing to reduce mosquito bites.

Many people have noticed it before, being in the same room, same evening, and walking away covered in bites while the person sitting next to you has little to none. It is not a coincidence, and it is not just bad luck.

Scientists have confirmed that mosquitoes genuinely prefer certain people over others. Research is now getting specific about why.

The first thing that draws a mosquito toward you is the carbon dioxide you exhale. They can detect it from dozens of metres away, and it is what gets them moving in your direction in the first place. As they close in to about ten metres, your body odour becomes the stronger signal. Get closer still, and your body heat and the moisture your skin releases help them lock onto a specific target.

Only female mosquitoes bite. They have highly sensitive receptors designed specifically to pick up these cues, and they use the combination of all three: breath, smell, heat, to decide who to go for.

Human skin constantly releases odorous compounds. Researchers estimate between 300 and 1,000 different ones at any given time. A recent study identified 27 of those compounds that mosquitoes actively respond to when choosing a target.

The people mosquitoes were most consistently drawn to tended to produce higher levels of a compound that forms when the skin breaks down its own natural oil, called sebum. 

This is a byproduct of your skin doing its normal job, except in some people, it is produced in quantities that mosquitoes find particularly attractive. Even a small increase in that compound was enough to meaningfully shift who got bitten.

Pregnant women in their second trimester also showed up as strongly preferred targets in lab conditions, likely linked to changes in body temperature and metabolic activity during pregnancy.

The popular theory that mosquitoes prefer certain blood types has no scientific backing. Researchers say the studies that suggested this involved too few participants to draw any real conclusions. Skin colour, hair colour and eye colour are equally irrelevant to mosquitoes.

Several studies have linked alcohol consumption (beer in particular) to increased mosquito attraction. Drinking raises your body temperature, increases the carbon dioxide you exhale, and alters your skin odour. In one study conducted in the Netherlands with 465 volunteers, those who had drunk beer in the previous 24 hours were 1.35 times more likely to be bitten than those who had not.

Loose-fitting clothing that covers the skin, repellent, and mosquito nets remain the most reliable measures. Researchers also suggest keeping meals light and reducing alcohol intake when you know you will be spending time in a mosquito-heavy environment.

Some people will always get bitten more than others. Most of it comes down to body chemistry and most of that is not something you can easily change.

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