What Attracts Mosquitoes to Some People More Than Others
Mosquitoes are attracted first by the carbon dioxide you breathe out, then by body odour, warmth, moisture and colours such as red, orange and black once they are close. Some people really are bitten more: a 2022 study in the journal Cell found the most attractive volunteer drew over 100 times the attraction of the two least attractive, linked to carboxylic acids on the skin. Blood type evidence is weak and mixed. Pregnancy, beer and a larger body all raise attraction.
Most articles on this question repeat the same list of suspects. Some hold up under the research and some do not. This guide sorts them by evidence, explains why the person next to you on the porch gets bitten less, and ends with what actually reduces bites at home.
What attracts mosquitoes, ranked by the evidence
| Factor | What the research shows | Strength of evidence |
|---|---|---|
| Carbon dioxide in breath | The main cue mosquitoes use to find a blood meal over long distances; it also switches on their interest in colours | Strong |
| Skin odour (carboxylic acids, lactic acid) | “Mosquito magnet” people produce significantly more carboxylic acids on their skin; differences stable over years | Strong |
| Colours of skin and clothing | After smelling CO2, mosquitoes fly towards red, orange, cyan and black; violet, blue and green drew no extra interest in tests | Strong (laboratory) |
| Body size | Bites shared among people sleeping together tracked each person’s surface area or weight | Moderate |
| Pregnancy | Pregnant women attracted twice as many malaria mosquitoes as non-pregnant women | Moderate |
| Beer | Two studies found more mosquito landings or attraction after drinking beer | Moderate |
| Heat and humidity | Guide landing and biting at close range | Strong as a close-range cue |
| Blood type O | One 2004 study found more landings on type O; a review says the ABO link was later refuted | Weak and mixed |
| Perfume and scented lotion | Wisconsin’s mosquito researchers say there is no evidence they attract mosquitoes | No good evidence |
| Vitamin B or garlic as protection | Controlled trials found no effect | Evidence against |
The table draws on the studies described below and on the 2021 review by Ellwanger, Cardoso and Chies in Current Research in Parasitology and Vector-borne Diseases, which summarises the field.
How a mosquito finds you: breath first, then skin, then colour
Host-finding happens in stages. The 2021 review describes carbon dioxide as the main molecule mosquitoes use to find a blood source over long distances: it triggers take-off and sustains flight. Carbon dioxide, lactic acid, acetone and ammonia are among the best-known human signals, and they work best in combination; a single cue on its own has a weaker effect.
Closer in, sight takes over. In a 2022 Nature Communications study, Alonso San Alberto and colleagues tracked more than 1.3 million mosquito flight paths in a wind tunnel. Without carbon dioxide, yellow fever mosquitoes showed no colour preference at all. After a puff of carbon dioxide, they were strongly attracted to wavelengths that people see as cyan, orange and red, while violet, blue, green and green-yellow objects drew no more interest than a plain control. Human skin of every tone is dominated by orange and red wavelengths, and filtering those bands out removed the attraction.
At landing range, heat, water vapour and skin chemicals decide whether a mosquito bites. That sequence is why repellents work on skin and clothing, not on the air around a yard.
Why mosquitoes bite some people more than others
Skin chemistry is the biggest single difference
The Rockefeller University study by De Obaldia, Vosshall and colleagues (Cell, 2022) collected skin odour from 64 volunteers who washed with unscented soap and wore nylon sleeves on their forearms for six hours. Mosquitoes were offered the sleeves in pairs. One volunteer scored 4 times higher than the next most attractive person and over 100 times higher than the two least attractive. The differences were stable over several years, and the most attractive people produced significantly more carboxylic acids in their skin emanations. Skin bacteria and genetics both shape that odour, according to the 2021 review, and twin studies show a genetic component to how often people are bitten.
This also answers a common worry about soaps and lotions. The Wisconsin mosquito programme at UW Madison states there is no evidence that wearing scented lotions or perfumes attracts mosquitoes, although floral scents do attract them in the laboratory.
Body size, pregnancy and beer
- Size. In two villages in the Gambia, Port, Boreham and Bryan (1980) analysed 2,339 blood meals from mosquitoes caught in shared bed nets and found each person’s share of bites tracked their share of the group’s surface area or weight. The review notes carbon dioxide output depends on metabolic rate and body mass.
- Pregnancy. Lindsay and colleagues (The Lancet, 2000) found pregnant women attracted twice the number of malaria mosquitoes as non-pregnant women, probably because of higher metabolic rate and heat output.
- Beer. Shirai and colleagues (2002) found mosquito landings rose significantly after volunteers drank 350 ml of beer. Lefèvre and colleagues (2010) found beer, but not water, increased attractiveness to malaria mosquitoes, and in their test exhaled carbon dioxide and body temperature did not explain it.
Does blood type attract mosquitoes?
The evidence is weak. Shirai and colleagues (Journal of Medical Entomology, 2004) found blood group O attracted more Asian tiger mosquitoes than other groups, but the difference was statistically significant only against group A, in 64 landing tests. The 2021 review states that the suggested ABO link “was later refuted”. Treat blood type as unproven, and skin odour as the far better explanation.
What attracts mosquitoes to your house
Water. CDC notes that mosquitoes need only a small amount of water to lay eggs, that an egg becomes an adult in 7 to 10 days, and that container-breeding Aedes mosquitoes fly only a few blocks in their lifetime. So container mosquitoes biting you at home are usually being raised close by, in buckets, plant saucers, toys, tyres, gutters and birdbaths. CDC advises emptying, scrubbing, turning over or covering such containers once a week, which beats the 7 to 10 day cycle. Culex mosquitoes, which bite from dusk to dawn, prefer more permanent water such as ponds and neglected pools.
That is why one neighbour’s neglected water can undo your efforts, a point we cover in our guide to mosquito control before an outdoor event. Professional barrier treatments are priced in our mosquito control cost guide, and what spraying does and does not do for disease risk is in mosquito spraying and disease risk.
When mosquitoes are most active
The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026, shows mosquito records building through summer to a September peak index of 182, more than four times the March low of 38. Biting midge (no-see-um) records peak much earlier, at 314 in June.
An index of 200 means a group is twice its usual share of everything people record that month, which removes the effect of more people being outdoors in summer. These are records of when people photographed mosquitoes, mostly outdoors, not bite counts. Not every small insect indoors is a mosquito; for the flies that turn up in the house, see how long flies live.
The invasive Asian tiger mosquito shows up in our state records too. Relative to all insect records, it is recorded slightly more often in Pennsylvania than in Florida or Texas.
What actually repels mosquitoes
CDC recommends EPA-registered repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol (PMD) or 2-undecanone, and advises not using OLE or PMD products on children under 3. Follow the label for how much to apply and how often.
Independent testing backs that list. Rodriguez and colleagues at New Mexico State University (Journal of Insect Science, 2017) found sprays containing DEET or p-menthane-3,8-diol were the most effective of the products they tested. Of five wearable devices, only one releasing the insecticide metofluthrin reduced mosquito attraction, and a citronella candle had no effect.
What does not work, or barely works
- Wristbands and most wearables: no effect in the 2017 test, apart from the metofluthrin device.
- Electronic and ultrasonic repellers: a Cochrane review found all 10 field studies showed no difference in mosquitoes caught with or without the device. Our review of ultrasonic pest repellers covers the wider evidence.
- Citronella candles and “mosquito plants”: Wisconsin reports relatively small reductions from citronella and no reduction from citrosa plants.
- Vitamin B and garlic: no effect in controlled trials.
- Backyard carbon dioxide traps: they catch large numbers but usually do not reduce bites. UF/IFAS’s Jonathan Day compared trapping far-flying mosquitoes to trying to capture all the grains of sand on the beach.
Frequently asked questions
What smells do mosquitoes hate?
The odours with real evidence are the EPA-registered repellents CDC lists: DEET, picaridin, IR3535, oil of lemon eucalyptus, PMD and 2-undecanone, applied to skin or clothing according to the label. Citronella candles give only small reductions in bites, citrosa plants none in tests, and catnip oil has not matched DEET in the laboratory. Scents in the air of a yard do far less than repellent on skin.
Do mosquitoes prefer fat or skinny people?
Larger people, but because of size rather than fat as such. A 1980 study of 2,339 blood meals in the Gambia found each person’s share of bites tracked their share of the group’s surface area or weight. Bigger bodies give off more carbon dioxide and heat, both mosquito cues. Skin odour still varies hugely between people of the same size, so a slim person can be the household mosquito magnet.
What is the best bait for mosquitoes?
Carbon dioxide, the same cue that draws mosquitoes to people from a distance. UW Madison’s mosquito programme lists CO2, ultraviolet or visible light, heat and octenol as the lures traps use. For a home, though, trapping rarely reduces bites, because mosquitoes keep arriving from elsewhere. Emptying standing water weekly and wearing repellent do more.
What is a mosquito’s worst enemy?
In the water, predators such as fish eat larvae, and mosquito control programmes have long used mosquito-eating fish, though Wisconsin researchers warn non-native fish can harm local ecosystems. Popular backyard predators disappoint: there is no evidence more bats reduce biting, purple martins do not control mosquitoes, and most frogs and tadpoles do not eat them. In practice, a dry container is the mosquito’s worst enemy.
Does blood type attract mosquitoes?
Not in any reliable way. A 2004 Japanese study found more landings on blood group O, but the difference was significant only compared with group A. A 2021 review of human attractiveness concluded that the suggested link between ABO blood groups and attraction was later refuted. Skin odour, especially carboxylic acid levels, explains far more of the difference between people.
Sources
- De Obaldia, Morita, Dedmon and colleagues including Vosshall, Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels, Cell, 2022.
- Alonso San Alberto, Rusch, Zhan, Straw, Montell and Riffell, The olfactory gating of visual preferences to human skin and visible spectra in mosquitoes, Nature Communications 13, 2022.
- Ellwanger, Cardoso and Chies, Variability in human attractiveness to mosquitoes, Current Research in Parasitology and Vector-borne Diseases, 2021.
- Port, Boreham and Bryan, The relationship of host size to feeding by mosquitoes of the Anopheles gambiae complex, Bulletin of Entomological Research 70(1), 1980.
- Lindsay and colleagues, Effect of pregnancy on exposure to malaria mosquitoes, The Lancet, 2000.
- Shirai and colleagues, Alcohol ingestion stimulates mosquito attraction, Journal of the American Mosquito Control Association, 2002.
- Lefèvre and colleagues, Beer consumption increases human attractiveness to malaria mosquitoes, PLoS ONE, 2010.
- Shirai and colleagues, Landing preference of Aedes albopictus on human skin among ABO blood groups, Journal of Medical Entomology, 2004.
- Rodriguez and colleagues, Efficacy of some wearable devices compared with spray-on insect repellents for the yellow fever mosquito, Journal of Insect Science, 2017.
- Enayati, Hemingway and Garner, Electronic mosquito repellents for preventing mosquito bites and malaria infection, Cochrane Database of Systematic Reviews, 2007.
- Ives and Paskewitz, Testing vitamin B as a home remedy against mosquitoes, Journal of the American Mosquito Control Association, 2005.
- CDC, Preventing Mosquito Bites; Life Cycle of Aedes Mosquitoes; Life Cycle of Culex Mosquitoes.
- University of Wisconsin Madison, Wisconsin Mosquitoes: home remedies, area repellents, carbon dioxide baited traps, and bats and birds.
- UF/IFAS News, Carbon dioxide mosquito traps no magic bullet, say UF experts, 2005.
- The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
