Geraniol Insect Repellent: What It Is and How Well It Works
The short answer
- Geraniol is the rose-scented compound in rose, geranium, citronella and lemongrass oils, and the best-studied plant-based repellent ingredient.
- It repels mosquitoes and ticks. In skin tests it gives about an hour of complete protection per application, so reapply every hour.
- Strength is everything. Below about 4% you get minutes, not an hour. Notch uses 5%.
The whole reason Notch exists is that I wanted a plant-based repellent people would actually enjoy putting on, without giving up on it working. So we started with the published research rather than the ingredient list on someone else’s bottle. One ingredient kept coming out ahead, especially once ticks were part of the picture: geraniol.
It’s the active in Nourish + Defend. Here’s what it is and what the studies actually show.
What geraniol is
Geraniol is a naturally occurring compound (a monoterpene alcohol, if you like chemistry) found in the essential oils of rose, geranium, palmarosa, citronella and lemongrass. It smells a lot like rose petals, which is why perfumers have used it for decades. The geraniol in Notch is plant-derived.
In a repellent it doesn’t kill anything. It keeps mosquitoes and ticks from landing, through scent and contact at close range, and because it’s volatile it works best freshly applied. You’ll sometimes see it called a pesticide. That’s a regulatory term: the EPA counts anything that repels pests as one, and geraniol is on the EPA’s minimum-risk list.
Is geraniol a pesticide or an insecticide?What “minimum-risk” means on a label
Does it work?
Yes, with two conditions: it has to be strong enough, and you have to reapply. Here’s the evidence, one bug at a time.
Mosquitoes
The best test is arm-in-cage. A volunteer puts a treated forearm into a cage of mosquitoes and the clock runs until the first bite. That window is the complete protection time.
In 2023, researchers at New Mexico State University ran 20 plant-based ingredients through that test. Only four lasted more than an hour: geraniol, clove, cinnamon and a fragrance compound called 2-phenylethyl propionate.1 The oils people usually reach for came in well behind. Citronella, lemongrass and peppermint managed about half an hour. Cedarwood, rosemary and thyme didn’t make it to 20 minutes.1 Of the four that worked, geraniol is the one that smells like roses rather than a spice rack.
A 2025 follow-up from the same lab asked the question I cared about most: how much do you actually need?2
16×
How much longer geraniol protected against mosquitoes at 5% than at 4%. Above 5%, more geraniol added almost nothing.
Lopez 2025, Insects2
How strength changes protection
1%0–3 min
3%0–6 min
4%3–9 min
5%~1 hr
Complete protection time against Aedes aegypti mosquitoes in arm-in-cage tests (Lopez 2025).
That cliff is why the percentage on the label matters. Plenty of botanical sprays use geraniol or geranium oil at 1% or less, mostly for the scent. The research says that buys you minutes.
Ticks
Ticks are the harder test, and the one most plant oils fail. In the 2023 study, citronella, lemongrass, peppermint, cedarwood and rosemary did no better against blacklegged ticks than untreated skin. Geraniol protected for more than an hour.1
In 2024, CDC researchers reviewed every minimum-risk ingredient with tick data: 19 of them, tested on skin.3 Three made it past an hour.
| Protection against ticks | Ingredients |
|---|---|
| 1 to 2 hours | Geraniol, cinnamon oil, clove oil |
| Under an hour | Citronella, lemongrass, peppermint, cedarwood, geranium oil, thyme, garlic, cornmint, spearmint |
| Under 10 minutes | Rosemary, soybean, castor, corn, cottonseed, linseed, sesame |
Complete protection time against blacklegged ticks, each ingredient at 10% in a lotion (Eisen 2024).
How to build a natural tick routine
How it compares to other botanicals
Ranked by the published skin tests against mosquitoes and ticks.
The Botanical Repellent Hierarchy
GeraniolBest-studied plant active. Repels mosquitoes and ticks.
OLE* / PMDLong-lasting, but weaker against ticks
Lemongrass · Clove · Cinnamon · SoybeanSome mosquito protection, but brief or no tick protection
Citronella · Peppermint · Cedarwood · Rosemary
*Oil of lemon eucalyptus (OLE) is refined from the leaves of the lemon eucalyptus tree and enriched in PMD (para-menthane-3,8-diol), which can also be made in a lab. Unlike the others here, it’s an EPA-registered active rather than a minimum-risk one, and it isn’t for children under 3.
The full side-by-side on BugRepellent.Guide
BugRepellent.Guide is a repellent research site run by the Notch team.
How we use it
Notch is 5% geraniol, right at the threshold where protection takes off, in a lotion rather than a spray so it goes on evenly, face and neck included. Glycerin keeps skin hydrated and bentonite clay keeps it from feeling greasy. It’s made for an evening on the patio or a walk with the dog, not an expedition. Don’t apply it to pets, and keep cats from licking treated skin.
Our label says reapply every hour, sooner if you’ve been swimming or sweating. That’s what the studies support, and I’d rather tell you that than promise all-day protection.
Why a lotion, not a sprayKeeping mosquitoes off your patioBug repellent and pets
Two questions I get a lot
Is geraniol the same as geranium oil?
No. Geranium oil is a whole essential oil that contains geraniol alongside citronellol and other compounds, and geraniol is usually a small share of it. A product listing geranium oil delivers much less geraniol than one listing geraniol itself at 5%.
Geranium oil vs. geraniol, compared
Is geraniol OK for sensitive skin?
Geraniol has a long history in cosmetics and perfumes. Like many fragrance compounds, it can bother some people with sensitive skin, so if your skin reacts easily, try a small amount on your inner forearm and wait a day before using it more widely. Stop using any repellent that causes a reaction.
Want to go deeper? BugRepellent.Guide’s geraniol page collects every geraniol study we’ve found, and it scores every product, ours included, by the same published rules.
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.
- Lopez AD, et al. Repellency of essential oils and plant-derived compounds against Aedes aegypti mosquitoes. Insects, 2025.
- Eisen L. Efficacy of unregulated minimum risk products to kill and repel ticks. Emerging Infectious Diseases, 2024.
