Does Lemon Verbena Oil Repel Mosquitoes? What Studies Measured

In a 2025 laboratory study, lemon verbena oil kept mosquitoes off volunteers' hands for a short time, and then the protection faded faster than DEET's did. That is a lab result about one oil from Ecuador, not a reason to rely on lemon verbena against bites, and we do not sell our oil as a repellent. If the question is protection from mosquito-borne disease, the answer comes from public-health guidance, and it names other ingredients.

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The one study that measured protection from bites

Parichanon and colleagues (2025, Insects) tested lemon verbena leaf oil from the Intag Valley in Ecuador, against the Asian tiger mosquito, Aedes albopictus. The oil was hydrodistilled (2 hours; the abstract calls it steam distillation, a mismatch in the paper) with a yield of 0.18%, and the main components were geranial 26.8%, neral 21.0%, limonene 7.2% and bicyclogermacrene 6.8%. The repellency test was a modified WHO arm-in-cage design: 10 volunteers (ethics approval and written consent reported), a treated 25 cm² patch on the hand, about 150 female mosquitoes, and a 3-minute exposure at each time point over 45 minutes.

Treatment (dose per cm² of skin)5 min15 min30 min45 min
Lemon verbena oil, 0.20 µl100%94.8%73.9%68.3%
Lemon verbena oil, 0.04 µlnot givennot givennot given38.6%
DEET, 0.04 µl96.2%80.5%76.4%59.6%

The figures are the paper's "protection efficacy" (PE), measured against ethanol-treated controls; the paper's exact formula was not reproduced here. The authors report that the oils did not differ significantly from DEET through 15 minutes, while at 45 minutes DEET was significantly higher; they attribute that to the oil's volatile components evaporating or oxidising and suggest encapsulation or stabilisers. The dose that produced half the effect (RD50) was 0.104 µl/cm² for the oil and 0.035 for DEET, so on this measure the oil needed about three times the dose.

The same paper is a reminder to read carefully. It gives RD50 as 0.104 in a table and 0.140 in the text, says the test dose was 0.02 in the methods and 0.04 in one comparison, and gives no adult-mosquito knockdown figure. The sample was 10 people, one mosquito species, and 45 minutes. That is a promising screening result and nothing like a label protection time.

Two other results that are easy to misread

The same study found the oil killed fourth-instar larvae of the same species (LC50 88.54 µl per litre of water after 24 hours). That is a larvicide result, a different question from biting. In a field oviposition test at 200 µl/l the oil cut egg-laying by 31.97% (235 eggs on treated sites against 344 on controls), against 63.69% for the second oil tested, palo santo.

An older study sits in the literature as an abstract: Gillij, Gleiser and Zygadlo (2008, Bioresource Technology) tested 12 oils from Argentinean aromatic plants against Aedes aegypti. Only the abstract was read. It says Aloysia citriodora was among three oils with the longest repellency times at 12.5% concentration, that repellency varied with the plant's geographic origin, and that the authors suggested limonene and camphor as the main responsible components. Notice that limonene, not citral, is named there, and that limonene is 7.2% of the Ecuadorian oil in 2025 and under 1% in three of four Palestinian oils in another study (Al-Maharik et al., 2024). Two oils sold as "lemon verbena" can differ a great deal in what the mosquito meets.

The arithmetic behind the dose

A dose per area is easy to misread. At 0.20 µl/cm², a 25 cm² patch received 5 µl of oil. At a density of about 0.869 g/ml (the value on our COA batch, used here only as an approximation, since the study did not report its oil's density) that is about 4.3 mg, and at roughly 20 drops per ml (50 µl a drop) about a tenth of a drop. For scale, 1 ml of a blend at our top skin dilution of 2% contains 20 µl of oil, and spread over 100 cm² that is 0.20 µl/cm². At 0.5% the same spread gives 0.05. This is a unit conversion, not a suggestion, because the study put oil on a patch of hand in a cage for minutes, and the conversion says nothing about what a lotion, a carrier or sweat would do. In another lab's arm-in-cage work, Lopez et al. (2025) note that the carrier changed an essential oil's protection time (clove oil lasted much longer in a lotion base than in ethanol, in earlier work they cite) and that composition varies between batches, which they offer as a reason studies of the same oil conflict. They also recall that DEET at 10% protected volunteers for 6 hours in their earlier study, when it was stopped, against a mean of 111.45 minutes for 10% clove oil.

Our own safety copy adds a practical problem. It says the oil can be mildly photosensitising and that treated skin should stay out of strong sun, while repellents are worn outdoors, in daylight, for hours. Our skin guidance is also 0.5% to 2% in a carrier, patch test first, away from children and pets (for pets see the pet question).

Why a lab result is not a repellent

CDC (page dated 28 August 2024) recommends EPA-registered repellents and lists six active ingredients to look for: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol (PMD) and 2-undecanone. On the alternatives it is blunt: "We do not know the effectiveness of non-EPA registered insect repellents, including some natural repellents." EPA's skin-applied list names eight actives: catnip oil, oil of citronella, DEET, IR3535, PMD, oil of lemon eucalyptus, picaridin and 2-undecanone. Lemon verbena, and citral, are not on either list.

EPA exempts some products from registration under its minimum-risk rule, but its conditions page (updated 26 February 2026) says such a label must not claim to control or mitigate organisms that pose a threat to human health, and gives "controls mosquitoes" as acceptable and a tick-and-Lyme-disease claim as not. So a product that tells you it will keep disease-carrying mosquitoes away has to be registered, and a product sold under the exemption cannot make that claim. Texts change, so check the current pages.

Where to go for a real decision

If you are travelling somewhere with dengue, malaria or Zika, ask a physician or a travel clinic and follow CDC guidance for the destination. For a garden evening, an EPA-registered product used as labelled is the documented choice. The oil itself belongs in a diffuser, a perfume or a candle, where its scent is the point.

Related reading: the overview of benefit claims and evidence, the safety guide and the scent-only cleaning formulations.

Lemon Verbena Essential Oil bottle

Lemon Verbena Essential Oil

Lemon Verbena Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

From $12.99

Shop Now →

Sources & Further Reading