Geraniol vs. Citronella vs. Lemongrass: Which Repels Mosquitoes Best?
The short answer
- Geraniol wins. In skin tests it protected against mosquitoes for over an hour and against ticks for one to two hours.
- Citronella and lemongrass oils managed 30-plus minutes against mosquitoes and did little against ticks. Citronella products lasted about 20 minutes in the classic head-to-head test.
- All three are minimum-risk plant actives. Whichever you buy, it should be named on the label with a percentage.
These three show up on natural repellent labels constantly, often side by side, and they’re related: geraniol is one of the compounds inside both citronella and lemongrass oil. People assume that makes them interchangeable. The tests say otherwise.
I’ll keep this short, because the comparison is the whole point.
Three oils, one table
The skin numbers come from a study that tested plant-based ingredients in a lotion on human arms against the yellow fever mosquito and the blacklegged tick, plus a CDC review of the same kind of tick test.12
| Mosquitoes | Ticks | Verdict | |
|---|---|---|---|
|
Geraniol A single compound. Soft, rosy scent. |
Over 1 hour | 1 to 2 hours | The one to look for. Mosquitoes and ticks, at about 5% or more. |
|
Citronella oil From citronella grass. The classic candle smell. |
30 minutes or more; about 20 minutes in real products3 | 10 minutes to 1 hour | Scent, not protection. Fades in minutes. |
|
Lemongrass oil From a close cousin of citronella grass. Bright and lemony. |
30 minutes or more | 10 minutes to 1 hour | A little better than its cousin on mosquitoes, still weak on ticks. |
The tick column is where the gap really opens. In the skin study, citronella and lemongrass oils didn’t protect against ticks at all; geraniol went past an hour.1
Real products are where citronella falls hardest. In the best-known head-to-head study of repellents, published in the New England Journal of Medicine, citronella products protected for only about 20 minutes.3 Strength matters for geraniol too: it needs to be at about 5%, and below 4% protection drops to minutes.4
How to build a natural tick routineThe full research on citronella, on BugRepellent.GuideEverything you need to know about geraniol
BugRepellent.Guide is a repellent research site run by the Notch team.
Reading the label
All three are on the EPA’s list of minimum-risk active ingredients, so you’ll find them in natural repellents sold without a registration number.5 Those rules require each active to be named with its percentage, so a blend that only says “essential oils” is hiding the one number that matters. And a candle or diffuser is a different product from a repellent on skin; a breeze carries the scent off, which is why a citronella candle helps only when you’re sitting right next to it.
What “minimum-risk” means on a labelKeeping mosquitoes off your patio
Why Notch uses geraniol
When I lined the three up, geraniol was ahead on mosquitoes and alone on ticks, so it wasn’t a hard call. Notch Nourish + Defend Botanical Insect Repellent uses 5% geraniol, right at the threshold where protection takes off, in a hydrating, non-greasy lotion that spreads evenly over exposed skin and smells faintly of rose. It repels mosquitoes and ticks, and for maximum protection you reapply every hour.
Want the bigger picture? Here’s our guide to natural repellents that actually work, and BugRepellent.Guide’s side-by-side of natural repellents.
Frequently asked questions
Is geraniol in citronella oil?
Yes. Geraniol is one of the compounds in citronella and lemongrass oils, but those oils are mixes of many compounds. A repellent made with geraniol itself delivers far more of it than the same amount of either oil.
References
- Luker HA, et al. Repellent efficacy of 20 essential oils on Aedes aegypti mosquitoes and Ixodes scapularis ticks in contact-repellency assays. Scientific Reports, 2023. Ingredients tested at 10% in a lotion; mosquito times in the table are from this study.
- Eisen L. Efficacy of unregulated minimum risk products to kill and repel ticks. Emerging Infectious Diseases, 2024. Tick times in the table are this review’s ranges for 10% lotions on human skin.
- Fradin MS, Day JF. Comparative efficacy of insect repellents against mosquito bites. New England Journal of Medicine, 2002.
- Lopez AD, et al. Repellency of essential oils and plant-derived compounds against Aedes aegypti mosquitoes. Insects, 2025.
- U.S. Code of Federal Regulations. 40 CFR 152.25, Exemptions for pesticides of a character not requiring FIFRA regulation.
