Lemongrass oil does repel mosquitoes, but its protection is modest compared to synthetic options. In lab testing, a 10% lemongrass lotion reduced mosquito attraction for about 60 minutes, while 10% DEET provided protection for six hours or more. That gap matters if you’re relying on lemongrass as your sole defense in a mosquito-heavy environment, but it can work well for casual, short-duration outdoor time.
How Lemongrass Repels Mosquitoes
The active ingredient in lemongrass oil is citral, which actually comes in two forms that together make up roughly 70% of the oil’s chemical composition. Citral interferes with the way insects detect and navigate toward hosts. It disrupts the nervous system pathways insects use to sense carbon dioxide and body heat, essentially jamming the signal that tells a mosquito you’re nearby. The oil also contains smaller amounts of geraniol and citronellal, both of which have independent repellent properties.
The effect is dose-dependent. Higher concentrations of lemongrass oil trigger a stronger avoidance response in biting insects. In one controlled experiment with stable flies (close relatives of mosquitoes in biting behavior), none of the insects fed on a surface treated with lemongrass oil, while nine fed on an untreated surface placed right next to it.
How Long Protection Lasts
This is where lemongrass falls short. In a study published in Scientific Reports that tested 20 essential oils head-to-head against DEET, a 10% lemongrass lotion provided meaningful protection for longer than 30 minutes but couldn’t match the two-hour mark that cinnamon and clove oils achieved. DEET at the same concentration lasted over six hours. The volatile compounds in lemongrass evaporate relatively quickly from skin, which is the core limitation of most plant-based repellents.
The carrier matters, too. When lemongrass oil was mixed with coconut oil rather than olive oil, protection time against common house mosquitoes (Culex species) jumped from about 97 minutes to 112 minutes. Against the yellow fever mosquito (Aedes aegypti, the species that also carries dengue and Zika), coconut oil as a base extended protection from roughly 59 minutes to 87 minutes. Choosing a heavier, slower-evaporating base oil can meaningfully extend how long the repellent works.
Which Mosquito Species It Works Against
Lemongrass doesn’t perform equally against all mosquitoes. Research comparing its effect on two major species found it was notably more effective against Culex mosquitoes, the type most responsible for nighttime biting and West Nile virus transmission. Against Aedes aegypti, the daytime-biting species linked to dengue and Zika, protection time was roughly 40% shorter.
For Culex mosquitoes, lemongrass oil in coconut oil kept biting rates below 1% for nearly two hours. Against Aedes, biting was similarly low during the protection window, but that window closed sooner. If your main concern is evening mosquitoes in your backyard, lemongrass is a reasonable short-term option. If you’re traveling to an area with dengue or Zika risk, it’s not sufficient on its own.
Getting the Most From Lemongrass Repellent
Because lemongrass oil is classified by the EPA as a minimum-risk pesticide, products containing it don’t go through the same registration and efficacy testing that DEET or picaridin products do. That means quality and concentration vary widely between brands. If you’re buying a commercial lemongrass repellent, look for one that lists the oil concentration on the label. Products below 5% are unlikely to provide meaningful protection.
For a DIY approach, mixing lemongrass essential oil into an unscented lotion or coconut oil at roughly 10% concentration is a reasonable starting point based on the research. That means about 10 drops of essential oil per tablespoon of carrier. You’ll need to reapply every 60 to 90 minutes for continuous protection, which is the main trade-off compared to a single application of DEET that lasts most of an evening.
A few practical strategies help extend its usefulness:
- Use coconut oil as a base. Its heavier consistency slows evaporation of the active compounds.
- Reapply frequently. Set a timer for 60 minutes if you’re outdoors in a high-mosquito area.
- Combine with other plant oils. Cinnamon oil provided protection for over 100 minutes in the same studies. Blending it with lemongrass may extend your coverage window.
- Layer with physical barriers. Long sleeves and pants reduce the skin area you need to protect, making reapplication less burdensome.
Skin Sensitivity and Pet Safety
Lemongrass essential oil can cause skin irritation, particularly at higher concentrations or with repeated use. Memorial Sloan Kettering Cancer Center has documented cases of delayed skin rashes from topical lemongrass oil, including one case where a massage therapist developed a reaction after prolonged professional use. If you’ve never applied it to your skin before, test a small patch on your inner forearm and wait 24 hours before using it broadly. People with sensitive skin or eczema should be especially cautious.
If you have pets, this is worth paying attention to. The ASPCA lists lemongrass as toxic to dogs, cats, and horses. The toxic components include the essential oils themselves and compounds called cyanogenic glycosides. Dogs and cats may develop stomach upset from exposure, while horses face more serious risks including difficulty breathing and weakness. Avoid applying lemongrass oil in areas where pets groom themselves or lick your skin, and be cautious with diffusers in enclosed rooms where pets spend time.