Why Do Mosquitoes Bite Some People More?
Mostly because of how a person smells to a mosquito, and that smell is shaped by skin chemistry, skin bacteria and genetics. Mosquitoes find people by breath carbon dioxide, then sight, heat and skin odor. Blood type has a weak, inconsistent effect at best. Vitamin B does nothing measurable in the study that tested it.
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Shop Now →How a mosquito finds you: a sequence, not one cue
Only female mosquitoes bite, because they need a blood meal to produce eggs. CDC notes that their antennae detect carbon dioxide from a person's breath and the movement of air, and their palps sense odor (CDC). Researchers have since shown how these cues are combined.
- Carbon dioxide wakes the system up. In a 2015 study in Current Biology, van Breugel and colleagues tracked mosquitoes in three dimensions and found that CO2 "activates a strong attraction to visual features" rather than just gating heat sensing. They argue mosquitoes can see humans from 5 to 15 meters away.
- Heat and odor close the distance. McMeniman and colleagues (Cell, 2014) knocked out a CO2 receptor gene in Aedes aegypti. The mutants were only slightly less attracted to live humans in a semi-field setting. Heat and odor cues appear to drive host seeking even without CO2.
- Skin odor decides who gets the bite. This is where people differ.
That sequence is why mosquito repellent advice is not one-size-fits-all, and it is the thread running through our explainer on how mosquito repellents work. A repellent works on the last step. The cues before it are the ones you cannot switch off, since you breathe and you are warm.
What differs between people: the evidence, with the mosquito species named
Studies use different mosquitoes, and results do not transfer automatically. We list the species so you can see how far each finding stretches.
| Factor | Study | Mosquito | What it found | How firm |
|---|---|---|---|---|
| Skin odor chemistry | De Obaldia et al., Vosshall lab (2022) | Aedes aegypti | People who stayed highly attractive over several years had higher levels of carboxylic acids in skin odor | Strongest recent evidence; one lab, human odor samples |
| Skin bacteria | Verhulst et al. (2011) | Anopheles gambiae | Highly attractive people had more skin bacteria but less diversity | Correlation in a small human sample; microbiota may be a marker, not a cause |
| Genetics | Fernandez-Grandon et al. (2015) | Aedes aegypti | Identical twins were highly correlated in attractiveness; estimated narrow-sense heritability 0.62 | Twin design supports a genetic share; hand odor, dual-choice lab test |
| Blood type | Shirai et al. (2004) | Aedes albopictus | In 64 landing tests, type O drew more landings than A, B and AB, significant only against A | Weak; authors found ABH antigens did not generally influence landing |
| Beer | Lefevre et al. (2010) | Anopheles gambiae | Beer increased attractiveness; water did not. Exhaled CO2 and body temperature had no effect | One semi-field trial in Burkina Faso |
| Pregnancy | Lindsay et al. (2000) | Anopheles gambiae complex | Pregnant women attracted about twice as many mosquitoes as non-pregnant women | Field study; relevant to malaria regions |
| Vitamin B supplements | Ives and Paskewitz (2005) | Anopheles stephensi | Found no effect of vitamin B supplementation | Larger than earlier tests; individual variation was large |
Sources are the study records themselves: De Obaldia et al. (published in Cell 2022; we read the bioRxiv preprint record), Verhulst, Fernandez-Grandon, Shirai, Lefevre, Lindsay and Ives and Paskewitz.
Where we take a position
"Blood type" is overrated. The widely repeated claim that type O people get bitten twice as often is not what the 2004 abstract says. It reports a significant difference only between types O and A, in one species, in 64 tests, and concludes that antigens did not generally influence landing preference. If blood type were the main driver, the effect would be clearer than that.
"I just taste better" is not a theory, but the underlying idea is right. The better-supported explanation is that attractiveness is a stable property of a person's odor profile. De Obaldia and colleagues identified people who were consistently highly or weakly attractive over years, and mosquitoes could tell them apart unless the odor of the highly attractive person was heavily diluted, which suggests concentration of odor drives the difference.
Nothing here tells you to change your diet. We found no study that shows a supplement, soap or food reduces how attractive a person is. Vitamin B is the clearest negative result. Our scorecard of mosquito repellent myths covers the other common ones.
What a repellent changes, and what it does not
A 2024 study in Scientific Reports by Fatou and Muller used 3D infrared tracking around forearms in a cage. Four 20 percent repellents (DEET, PMD, icaridin and EBAAP, in ethanol) all substantially reduced bites compared with an untreated arm. Yet mosquitoes still made brief, repeated contact with treated skin. The authors read this as contact-triggered disengagement rather than repelling from a distance (Europe PMC record). Applied to the question of this page: your odor profile decides how many mosquitoes come close, and a registered repellent acts when they arrive. That is why an attractive person needs to follow the label carefully, including reapplication, rather than expecting a spray to make them invisible.
How to read the next "why mosquitoes love you" headline
- Which mosquito? A result in Anopheles may not hold for Aedes.
- Was it landing, attraction in a tube, or bites outdoors?
- How many people were tested, and was there an untreated or water control?
- Does the abstract say what the headline says? In the blood type case it did not.
What the studies cannot tell you
- Whether you will get more bites tomorrow. These are mostly lab or semi-field tests of attraction, and attraction is not the same as being bitten in a real yard.
- Whether your reaction to a bite is the same as another person's. We did not find a source in this set on why bites swell more on some people, so we do not speculate.
- Which species is around you. The findings above come from Aedes and Anopheles; Culex and others are not covered in this set.
- How a given repellent interacts with your odor profile. That is not tested in these studies.
What to do with an attractive-to-mosquitoes body
You cannot change your genetics or your breath, so work on the other sides of the equation. CDC advises:
- Use proven EPA-registered insect repellents, following the label.
- Wear loose-fitting, long-sleeved shirts and pants.
- Use screens on windows and doors and repair holes; use air conditioning if available.
- Once a week, empty and scrub, turn over, cover or throw out items that hold water, such as buckets, birdbaths and flowerpot saucers. This is the step that lowers how many mosquitoes there are to find you, and it is the center of our backyard mosquito guide.
Be careful about one more thing. If you are the person who always gets bitten, a plant oil or scent product will not change that, and we do not claim our Lemon Eucalyptus Essential Oil does. It is not an EPA-registered repellent. The CDC-listed active ingredient oil of lemon eucalyptus is a refined material with its own labeling, which we explain in does lemon eucalyptus repel mosquitoes and in our OLE guide. CDC says not to use OLE or PMD products on children under 3. A pediatrician or pharmacist can help you choose for a child.
If you are in a region with mosquito-borne illness, or pregnant, ask a physician or travel-medicine clinic about protection, because the studies above suggest your risk of being bitten may be higher, and the best measures depend on where you are.
FAQ
Why do mosquitoes bite me and not my partner?
The best-supported answer is differences in skin odor, which are partly genetic. In the twin study, relative attraction had an estimated heritability of 0.62.
Does blood type matter?
A little in one study, and not enough to plan around. Type O drew more landings than A, but the study's authors concluded blood group antigens did not generally explain landing preference.
Does vitamin B stop mosquitoes?
The 2005 study found no effect of vitamin B supplementation on the attractiveness of skin odors.
Does drinking beer make mosquitoes bite more?
In one semi-field study with malaria mosquitoes in Burkina Faso, beer increased attractiveness and water did not. Treat that as one result for one species.
Last reviewed: October 2026
Lemon Eucalyptus Essential Oil
Lemon Eucalyptus Essential Oil from our own shop, in sizes from 0.5 oz to bulk.
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Shop Now →Sources & Further Reading
- CDC: About mosquitoes
- CDC: Preventing Mosquito Bites
- van Breugel F et al. (2015). Mosquitoes use vision to associate odor plumes with thermal targets. Curr Biol 25(16):2123-2129
- McMeniman CJ et al. (2014). Multimodal integration of carbon dioxide and other sensory cues drives mosquito attraction to humans. Cell 156(5):1060-1071
- De Obaldia ME et al. (2022). Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels. bioRxiv preprint; published in Cell 185(22)
- Verhulst NO et al. (2011). PLoS One 6(12):e28991
- Fernandez-Grandon GM et al. (2015). PLoS One 10(4):e0122716
- Shirai Y et al. (2004). J Med Entomol 41(4):796-799
- Lefevre T et al. (2010). PLoS One 5(3):e9546
- Lindsay S et al. (2000). Effect of pregnancy on exposure to malaria mosquitoes. Lancet
- Ives AR, Paskewitz SM (2005). J Am Mosq Control Assoc 21(2):213-217