Oil of lemon eucalyptus (OLE) is a refined and stabilized extract of the lemon eucalyptus tree, recognized by the U.S. CDC and EPA as an effective mosquito repellent. Lemon eucalyptus oil is the raw essential oil from the same tree, which has not passed CDC efficacy testing. The two products sound identical but they are not. OLE contains a higher concentration of the active compound (PMD or p-Menthane-3,8-diol) than raw lemon eucalyptus oil, which is why OLE works as a repellent and raw oil does not.
This is a small but important distinction that gets confused constantly. Here is what each one actually is, and why the difference matters when you are choosing a mosquito repellent.
The lemon eucalyptus tree
Both products come from the same source: Corymbia citriodora, the lemon-scented gum tree native to Australia. The leaves of this tree contain a complex mix of essential oil compounds with a strong citrus-eucalyptus scent.
The raw essential oil contains roughly 60 to 80 percent citronellal as its primary compound, along with smaller amounts of citronellol, isopulegol, geraniol, and trace amounts of PMD (p-Menthane-3,8-diol). The PMD content in raw lemon eucalyptus oil is typically under 1 percent.
Lemon eucalyptus oil (the raw essential oil)
When you buy a bottle labeled "lemon eucalyptus essential oil" from a health food store or essential oil retailer, you are buying the unrefined extract of the lemon eucalyptus tree leaves. This is commonly used for:
• Aromatherapy (the citrus-eucalyptus scent)
• Diffusers for fragrance
• DIY cosmetics and skincare
• DIY cleaning products
Lemon eucalyptus oil has not passed the EPA efficacy testing required for registration as a mosquito repellent. Some users apply it diluted in carrier oil as a folk mosquito deterrent. The peer-reviewed data on its repellent effect at typical DIY concentrations shows a brief and weak effect (often under 1 hour). It is not CDC-recognized.
If you see "lemon eucalyptus oil" or "essential oil of lemon eucalyptus" on a mosquito repellent label without the specific terms "OLE" or "PMD" or "p-Menthane-3,8-diol," the product is likely using the raw oil, which is not the same as the CDC-recognized active.
Oil of lemon eucalyptus (OLE)
Oil of lemon eucalyptus is the EPA-registered term for a refined extract of lemon eucalyptus oil that has been processed to increase the concentration of PMD. The refining process either extracts and concentrates the naturally occurring PMD from the raw oil or chemically converts citronellal (the main raw compound) into PMD.
OLE typically contains 60 to 70 percent PMD. This is roughly 60 to 100 times the concentration of PMD found in raw lemon eucalyptus oil.
The EPA recognizes OLE products at 8 percent or higher PMD concentration as effective mosquito repellents. At 8 percent PMD, OLE-based sprays provide 4 to 6 hours of mosquito protection comparable to lower-concentration DEET.
Common OLE-based repellent products:
• Repel Lemon Eucalyptus Insect Repellent (OLE concentration about 30 percent)
• Cutter Lemon Eucalyptus Insect Repellent (OLE about 30 percent)
• Superbloc Bloc Off Spray (PMD concentration 8 percent in alcohol-free water-based formulation)
• Murphy's Naturals Lemon Eucalyptus Oil Insect Repellent (OLE about 30 percent)
Each of these products is EPA-registered and uses OLE as the active ingredient.
Why the difference matters
If you are trying to repel mosquitoes:
• is not reliable as a repellent. The PMD content is too low to deliver meaningful protection.
• are CDC-recognized and proven effective.
The distinction matters because well-meaning users sometimes try to use raw lemon eucalyptus oil from a health food store as a mosquito repellent, get poor results, and conclude that "natural mosquito repellent does not work." The real explanation is that they used the wrong form of the lemon eucalyptus extract.
What about "lemon eucalyptus" as the active ingredient label
On EPA-registered repellent labels, the active ingredient might be listed in any of these ways:
• "Oil of lemon eucalyptus"
• "OLE"
• "p-Menthane-3,8-diol"
• "PMD"
• "Para-menthane-3,8-diol"
All five terms refer to the same active. PMD and p-Menthane-3,8-diol are the chemistry names. OLE is the EPA's preferred regulatory term. "Oil of lemon eucalyptus" is the consumer-friendly name.
If you see "lemon eucalyptus essential oil" on a repellent label without any of the above clarifications, treat it with skepticism. It may be raw essential oil rather than the refined OLE.
Other "lemon" repellent terms you might encounter
The naming around lemon-scented repellents gets confusing fast. A short clarification:
• different plant (Cymbopogon citratus), different compound. Not OLE. Not CDC-recognized.
• different plant (Melissa officinalis). Not OLE. Has very mild repellent effect at high concentration, not CDC-recognized.
• different plant. Decorative, not repellent.
• different plant. Not repellent.
• related but different. Citronella oil comes from Cymbopogon nardus and has a similar citrus scent but is not the same as lemon eucalyptus oil. Not CDC-recognized as a topical repellent.
• the source of both raw lemon eucalyptus oil and refined OLE.
• broader term covering many eucalyptus species. Most eucalyptus oils are not lemon eucalyptus and not relevant to repellent.
When in doubt, look for "PMD" or "p-Menthane-3,8-diol" or "Oil of lemon eucalyptus" on the back of the bottle as the active ingredient. These are the regulatory terms that identify a real, CDC-recognized repellent.
How OLE-based repellents are made
Two main processes are used to produce OLE:
Natural extraction and concentration
The raw essential oil is steam-distilled from lemon eucalyptus tree leaves. The resulting oil is then refined through additional distillation to concentrate the PMD content. This is the more traditional process and produces "natural" OLE.
Catalytic conversion
The citronellal compound in raw lemon eucalyptus oil is chemically converted to PMD using mild acid catalysts. This converts the abundant raw compound (citronellal) into the more potent repellent compound (PMD). The resulting OLE has very high PMD concentration.
Either process produces an EPA-registerable active ingredient. Products may use either approach without distinguishing on the label.
Common questions about lemon eucalyptus and PMD
Is OLE the same as PMD?
Effectively yes. OLE (oil of lemon eucalyptus) is the regulatory term for an extract whose active compound is PMD (p-Menthane-3,8-diol). PMD is what makes OLE work.
Why does my essential oil bottle of "lemon eucalyptus oil" not repel mosquitoes?
The raw essential oil contains very little PMD (under 1 percent). PMD is the compound that repels mosquitoes. The raw oil's citrus-eucalyptus scent is mostly from citronellal, which is a much weaker repellent than PMD.
Can I refine raw lemon eucalyptus oil at home to make OLE?
No. The refining process requires specific industrial distillation equipment or chemical catalysis. Home essential oil setups cannot produce OLE.
Is OLE actually natural?
OLE is plant-derived (from the lemon eucalyptus tree) but goes through industrial processing to concentrate PMD. Whether this counts as "natural" depends on your definition. The EPA accepts OLE as a plant-derived active. Some users consider OLE less "natural" than raw essential oil because of the processing.
Why is OLE the only CDC-recognized plant-based repellent?
The CDC requires lab and field testing showing protection comparable to DEET. Most plant essential oils (raw lemon eucalyptus, citronella, peppermint, lavender) provide brief weak protection that fails CDC standards. OLE is unusual because the refining process produces a concentrated active that does pass.
Is PMD safer than OLE?
They are essentially the same active. Some users prefer products labeled "PMD" rather than "OLE" because the term sounds more precise and chemical. The repellent compound is identical.
What about products labeled "OLE 30 percent"?
This means the product contains 30 percent oil of lemon eucalyptus, where the OLE itself contains roughly 60 to 70 percent PMD. The net PMD concentration in a 30 percent OLE product is about 18 to 21 percent. EPA registration is based on the OLE percentage, but the PMD content determines protection duration.
How Superbloc uses PMD
Superbloc's 8 percent PMD formulation specifies the PMD content directly rather than the OLE percentage. This is the same active you find in Repel Lemon Eucalyptus or Cutter Lemon Eucalyptus, just labeled with the chemistry name.
We chose the 8 percent PMD concentration because it sits at the CDC's effective threshold while remaining gentle enough for our alcohol-free water-based formula and our 6-month minimum age. Higher concentrations (20 to 30 percent PMD) are also EPA-registered but typically require alcohol carriers and a 3-year minimum age.
Browse:
• 8 percent PMD, alcohol-free, water-based with aloe and chamomile, safe from 6 months.
Featured in goop and Harper's Bazaar.
Written by Tanya Lee, Founder, Superbloc
