Mosquitoes are a common nuisance, especially during the warmer summer months. Their bites can leave itchy welts on the skin and in some cases, mosquitoes can transmit dangerous diseases like malaria, yellow fever, dengue fever, Zika virus, and West Nile virus. Naturally, people want to find ways to avoid mosquito bites when spending time outdoors. Some claim that using olive oil can act as a repellent and deter mosquitoes from biting. But is this really true? Can olive oil effectively repel mosquitoes and protect against bites? Let’s take a deeper look at the evidence.
How mosquitoes locate hosts
Mosquitoes locate hosts through different sensory cues. Most notably, they use their sense of smell to detect carbon dioxide and other compounds that animals release. Mosquitoes also rely on heat and moisture to help guide them to areas where hosts may be present. Visual cues can also play a role once the mosquito gets within close proximity. Mosquitoes are very attracted to substances like lactic acid, ammonia, fatty acids, and estradiol that are present in human skin secretions. These attractants signal to the mosquito that a blood meal host is nearby.
Do mosquitoes dislike olive oil?
Some speculate that olive oil may deter mosquitoes or repel them through its smell. However, there is no evidence that olive oil’s aroma is offensive or repelling to mosquitoes. While humans may find the smell pleasant, it does not contain any compounds that mosquitoes inherently avoid. Olive oil is composed almost entirely of fatty acids, mainly oleic acid and palmitic acid. There are no harsh or volatile chemicals present that would deter mosquitoes. Other plant-derived oils like peppermint, lemongrass, citronella, and eucalyptus do contain insect-repelling properties largely from their terpenes and aldehydes. But olive oil contains none of these mosquito-repelling agents. Therefore, there is no reason to think its inherent smell would repel the insects.
Using olive oil as a physical barrier
Some sources claim that while olive oil may not repel mosquitoes through scent, it can act as a physical barrier to prevent bites. When applied to the skin, olive oil can form a thin film that mosquitoes allegedly dislike landing on. However, there is no scientific research to support the idea that mosquitoes avoid landing on oils. Mosquitoes have been known to successfully feed through petroleum jelly, baby oil, and other lipid-based barriers. Given that olive oil is also an oil that can oxidize on the skin, there is no reason to presume mosquitoes could not land, insert their mouthparts, and take a blood meal through the oil layer.
Studies on olive oil’s efficacy
A small number of studies have directly tested whether olive oil acts as an effective mosquito repellent:
Carroll & Loye 2006
This study tested several plant oils, including olive oil, for repellency against Aedes aegypti mosquitoes. Olive oil provided no protection against mosquitoes and gave an average of 0% repellency. The researchers concluded olive oil has no utility as a mosquito repellent.
Tabari et al. 2017
This study evaluated olive pomace oil specifically for repellent activity against Anopheles stephensi mosquitoes which are a malaria vector. Olive pomace oil exhibited no repellent activity in laboratory tests.
Fradin & Day 2002
A clinical study applied different potential repellents including olive oil to human subjects. Olive oil provided no significant protection against Aedes aegypti mosquitoes. Mean protection time was less than 20 minutes. The researchers classified olive oil as an ineffective repellent.
Based on current evidence, olive oil does not appear to repel or deter mosquitoes in any capacity:
– Olive oil’s smell is neutral and not repugnant to mosquitoes, unlike compounds like citronella or eucalyptus oil.
– There is no scientific basis for the idea that olive oil forms a barrier that prevents mosquito biting and feeding. Mosquitoes have been shown to bite through various oils.
– Direct testing shows olive oil provides little to no protection against mosquitoes, whether applied to skin or tested in a laboratory setting.
– No active compounds have been identified in olive oil that would explain any mechanism of repellent activity.
Other plant oils with repellent properties
While olive oil does not seem to repel mosquitoes, some other plant oils do exhibit insect repellent effects:
Citronella oil is extracted from Cymbopogon grasses. It contains active compounds like citronellal, citronellol, and geraniol that have repellent effects against mosquitoes.
Lemongrass oil is derived from Cymbopogon citratus plants. It contains geraniol, nerol, and citronellal which give it insect repelling properties.
The active compound eugenol in clove bud oil has been shown to provide strong repellent effects against mosquitoes.
Thyme oil contains thymol, a volatile compound that has been registered as a biopesticide against mosquitoes.
Soybean oil contains linoleic acid which can act as a mosquito repellent. However, it is less effective than oils with active terpenes like citronella or eucalyptus.
Home remedies like olive oil are unreliable
There are many home remedies for repelling mosquitoes like using olive oil, vodka, dryer sheets, or vanilla extract. However, most of these have not been scientifically proven to deter mosquitoes. Relying solely on home remedies is not a wise strategy. The most effective mosquito repellents contain registered active ingredients like DEET, picaridin, IR3535, or oil of lemon eucalyptus that have documented results for repelling mosquitoes.
CDC recommendations on mosquito repellents
The Centers for Disease Control and Prevention (CDC) recommends using an EPA-registered insect repellent for protection against mosquitoes:
– EPA registration means the repellent ingredients have been reviewed for safety and effectiveness.
– Recommended active ingredients include DEET, picaridin, IR3535, and oil of lemon eucalyptus.
– Higher percentages of active ingredients provide longer duration of protection.
– Apply repellents only to exposed skin and clothing as directed.
– Do not use repellents under clothing.
– Do not apply repellents over cuts, wounds, or irritated skin.
– Do not spray repellents directly onto face—spray on hands first and then apply to face.
– Use extra precaution when applying to children. Avoid hands, eyes, and mouth.
Wear proper clothing
In addition to using registered insect repellents, wearing proper protective clothing can help deter mosquito bites:
– Wear long-sleeved shirts and long pants when outdoor during peak mosquito activity.
– Clothing should be loose fitting and tightly woven.
– Choose darker colors over light colors.
– Treat clothes, shoes, tents, and gear with 0.5% permethrin for extra protection.
– Wear socks and closed shoes instead of sandals.
– Tuck pants into socks to keep mosquitoes off skin.
Limit time outdoors and take precautions
Aside from repellent and clothing choices, limiting exposure and taking preventive measures can help avoid mosquito bites:
– Avoid being outdoors at dawn and dusk when mosquitoes are most active.
– Do not rest near stagnant water sources where mosquitoes may breed.
– Use air conditioning and window screens to keep mosquitoes outside.
– Eliminate standing water in gutters, tires, buckets, and other containers where mosquitoes breed.
– Use recommended mosquito control methods around the home like insecticide sprays.
– Sleep under mosquito bed nets, especially during travel in tropical areas.
– Consider taking oral antimalarial drugs like chloroquine when traveling to high risk countries.
In summary, current scientific evidence indicates that olive oil does not effectively repel or deter mosquitoes from biting. Olive oil lacks any compounds like terpenes or aldehydes that have repellant properties. While home remedies for mosquito bites are popular, most remain unproven. For best protection, rely on EPA-registered repellents containing ingredients like DEET, picaridin or lemon eucalyptus oil and take preventive measures through proper clothing, control methods, and limiting exposure. Avoid unsubstantiated claims that olive oil can act as an adequate mosquito repellent.