Does Citronella Actually Repel Mosquitoes? What the Evidence Says

TL;DR — Key takeaways

• Citronella oil does repel mosquitoes, but only briefly — most studies show meaningful protection for roughly 30 minutes to 2 hours before it needs reapplying.
• Its active compounds evaporate quickly, so a single application rarely lasts a full evening outdoors.
• Raw citronella oil is not the same as PMD (para-menthane-3,8-diol) — a refined, longer-lasting active that the CDC rates as comparable to lower-concentration DEET.
• Citronella candles offer little reliable protection in open, breezy outdoor settings.
• For longer-lasting, evidence-based, DEET-free protection, look for PMD rather than plain citronella oil.

Citronella is one of the most recognised names in natural insect protection — it scents candles, sprays, wristbands and garden torches every summer. But does citronella actually repel mosquitoes, or is it mostly marketing? The short answer: it works, just not for very long. Below we look at what the science says, how raw citronella oil compares to the refined active PMD, and how to get dependable protection without DEET.

What is citronella?

Citronella oil is an essential oil distilled from the leaves and stems of Cymbopogon grasses — most commonly Ceylon-type (Cymbopogon nardus) and Java-type (Cymbopogon winterianus) lemongrass relatives. Its insect-repelling effect comes mainly from volatile aromatic compounds such as citronellal, geraniol and citronellol, which mask the human scents (carbon dioxide, lactic acid, body heat cues) that mosquitoes use to find us.

The U.S. Environmental Protection Agency (EPA) has registered citronella as a biopesticide for decades and considers it to have minimal risk to human health when used as directed. So the question is not really about safety — it is about how effective and how long-lasting it is in real-world conditions.

Does citronella repel mosquitoes — yes or no?

Yes — citronella genuinely repels mosquitoes. Multiple laboratory and field studies confirm that freshly applied citronella reduces mosquito landings and bites compared with using nothing at all. The problem is duration, not whether it works at the moment of application.

A widely cited systematic review of plant-based repellents (Maia & Moore, Malaria Journal, 2011) found that citronella can be as effective as DEET in the first few minutes after application, but its protection drops off rapidly as the oil evaporates. Without a fixative to slow evaporation, complete protection often falls below an hour.

How long does citronella last?

This is citronella’s real weakness. Because its active molecules are highly volatile, they disperse from the skin within a short window. Reported ‘complete protection times’ for plain citronella formulations typically range from about 30 minutes to 2 hours, after which mosquitoes begin biting again.

Some formulations extend this by blending citronella with fixatives such as vanillin, which can roughly double the protection time in lab settings. Even so, you will usually need to reapply raw citronella far more often than a PMD or DEET product to stay protected through an evening barbecue, a hike, or a night in a mosquito-heavy region.

Citronella oil vs PMD vs DEET

Here is the distinction that matters most — and the one most product labels blur. Raw citronella oil is not the same thing as PMD (p-menthane-3,8-diol), the refined active that the U.S. Centers for Disease Control and Prevention (CDC) lists alongside DEET for longer-lasting protection. PMD is a single, stable molecule; it is most often produced from oil of lemon eucalyptus (Corymbia citriodora), but it can also be derived from citronella. In other words, the candle on your patio and the proven repellent active can come from the same plant family — yet behave completely differently on your skin.

The takeaway: if you want a plant-based repellent that lasts, choose one built on PMD — not raw citronella oil. We cover this difference in more detail in our guide on whether natural insect repellents actually work and our comparison of DEET versus plant-based repellents.

Do citronella candles and torches work?

Citronella candles create a small zone of scented smoke, but their real-world effect is limited. Outdoors, even a light breeze disperses the vapour, and studies have found that citronella candles reduce bites only modestly — and far less than a repellent applied directly to skin. They can add a pleasant ambience, but they are not a reliable substitute for a proper repellent if mosquitoes are active.

• Candles only protect a small, still pocket of air close to the flame.
• Wind, movement and open spaces sharply reduce their effect.
• Skin-applied repellents remain the most dependable barrier against bites.

How to get reliable DEET-free protection

If you like the idea of a plant-based repellent but want it to actually last, the practical answer is to choose a product built around PMD rather than plain citronella oil. This gives you a natural, DEET-free active with clinical backing and a protection window measured in hours, not minutes.

How incognito® helps

At incognito® we skip DEET entirely and build our protection around PMD (para-menthane-3,8-diol), the refined plant-based active — derived in our formula from Cymbopogon winterianus (Java citronella). Our Insect Repellent Spray (100ml) is DEET-free, vegan, biodegradable and clinically proven, and it is recommended against both mosquitoes and ticks — giving you the natural credentials people hope for from citronella, but with the lasting performance raw citronella oil can’t deliver. It is a simple way to enjoy the outdoors without constant reapplication or synthetic chemicals.

FAQs

Does citronella actually keep mosquitoes away?
Yes, but only for a short time. Freshly applied citronella repels mosquitoes effectively, yet its protection usually fades within 30 minutes to 2 hours as the oil evaporates.

Is citronella oil the same as PMD?
No. Citronella oil is the raw essential oil and is short-lived. PMD (para-menthane-3,8-diol) is a refined active molecule that lasts several hours and is CDC-recognised. PMD can be produced from lemon eucalyptus or from citronella, but it behaves very differently from raw citronella oil.

How often do I need to reapply citronella?
Often — typically every 30 to 60 minutes outdoors, and more frequently if you are sweating or it is breezy. This is why many people switch to a longer-lasting PMD-based repellent.

Do citronella candles work against mosquitoes?
Only a little, and mainly in still air close to the candle. Outdoors and in any breeze, their effect is small. A skin-applied repellent is far more reliable.

What is a longer-lasting natural alternative to citronella?
PMD (para-menthane-3,8-diol), a refined plant-based active, is the leading evidence-based alternative. It is DEET-free and offers several hours of protection per application.

Is citronella safe to use?
Citronella is registered by the EPA as a minimal-risk biopesticide and is generally considered safe when used as directed. Always follow the product label and patch-test if you have sensitive skin.

Sources

• Maia MF & Moore SJ. Plant-based insect repellents: a review of their efficacy, development and testing. Malaria Journal, 2011.
• U.S. Centers for Disease Control and Prevention (CDC) — Prevent Mosquito Bites.
• U.S. Environmental Protection Agency (EPA) — Skin-Applied Repellent Ingredients (oil of citronella, OLE/PMD).
• European Centre for Disease Prevention and Control (ECDC) — Personal protective measures against mosquito bites.

This article is for general information only and is not medical advice. If you are travelling to an area with a risk of mosquito- or tick-borne disease, follow official guidance and consult a healthcare professional. Always read and follow the product label.