Why Do Mosquitoes Bite Some People More Than Others? (The Honest Science, Not the Meetha Khoon)

Every Indian family has one. The cousin who comes back from the terrace with eleven bites while everyone else has none. The uncle who says "mera khoon meetha hai" as if it were a medical fact. It isn't — but the pattern behind it is real, measurable and surprisingly specific.

How does a mosquito find you in the first place?

Three signals, in order of distance.

Carbon dioxide first. A female mosquito can pick up the CO2 in your breath from several metres away, well before she can see or smell you. She flies upwind along the plume until the other signals take over. More exhaled CO2 means a bigger plume — which is why larger people, pregnant women and anyone who has just climbed four floors of stairs get found first.

Body heat and moisture next. Within about a metre, she switches to heat and humidity. A warm, slightly damp body is a landing strip; a cool, dry one is harder to lock onto.

Skin smell last, and this is the big one. Your skin is covered in bacteria that turn sweat into hundreds of volatile compounds, and mosquitoes have receptors tuned to specific ones. A study that tracked the same volunteers for three years found that the "mosquito magnets" had consistently higher levels of certain fatty acids on their skin — and stayed magnets the whole time, regardless of what they ate or how they washed. Your skin chemistry is mostly inherited. You didn't do anything wrong.

Does blood group actually matter?

Barely. One often-quoted study found that Type O skin attracted slightly more landings than Type A, but the effect was small and later work hasn't reproduced it cleanly. Blood group is at best a minor tiebreaker. CO2, heat and skin smell decide the match long before a mosquito finds a vein.

Why do I get bitten and my partner doesn't?

Usually a combination of three things.

1. You're the bigger CO2 source. Larger body, faster breathing, or you were the one talking — talking pushes out noticeably more CO2 than sitting quietly.
2. You're warmer. Just exercised, just ate a heavy meal, slightly feverish, or simply naturally warm.
3. You react more. Some people barely respond to mosquito saliva — a tiny bump that's gone in an hour. Others get the 2 cm welt that itches for two days. Two people on the same terrace often get the same bites; only one of them notices.

That third point explains most "they never bite me" claims. They do. The person just doesn't show it.

Does what I wear or drink change anything?

A little, and these are the levers you actually control.

• Dark clothing. Mosquitoes see you as a dark shape against a lighter sky. Navy, black and dark green at dusk make you easier to spot. Light, loose cotton helps — and loose matters, because a mosquito bites through tight fabric but not through a gap of air.
• Alcohol. A small study found that beer drinkers got more landings, most likely because of body heat and breathing rather than the beer itself. The evening-drink-on-the-balcony effect is real.
• Sweat. Fresh sweat is mildly attractive; sweat that has sat on the skin for a few hours and been worked over by bacteria is very attractive. The post-gym, pre-shower window is peak bite time.
• Strong fragrance. Floral perfumes can add to the signal. It's not a huge effect, but it's a free one to remove.
• Garlic, vitamin B, bananas. No reliable evidence either way. Eat what you like.

What actually reduces bites, in order?

1. Cover up at dusk. Loose, light, long sleeves and trousers. This single step removes most of the exposed skin a mosquito can land on.
2. Keep the air moving. A fan on medium does more than most people expect — mosquitoes are weak fliers, and a steady breeze both disperses your CO2 plume and makes landing hard.
3. Treat the skin the sleeves don't cover. A repellent cream or roll-on on ankles, wrists and neck.
4. Deal with the ones that still arrive. None of the above stops the one mosquito that found you anyway. For that there is only contact: a racket at home, or PocketPip — a 96 g, 20 cm, USB-C rechargeable pocket mosquito zapper with a 3-layer guarded mesh and about 7 days per charge — on the balcony, in the car, or anywhere the racket didn't come with you.

If you'd rather fix the room than yourself, start with the full home routine — removing breeding water does more than any amount of long sleeves.

If you're the family mosquito magnet, the other half of the problem is where the mosquitoes come from. The apartment city guide covers why your seventh-floor flat still has them, and the explainer on whether zappers actually work covers the physics of the contact fix.