Eucalyptol, also called 1,8-cineole, is a monoterpene with a cool, fresh, camphor-like smell that makes up most of eucalyptus oil. It also occurs in many other aromatic plants and in small amounts in some cannabis. Most research on it comes from cell and animal studies, and it is also studied as an ingredient in topical formulations.
Key facts
- Other name
- 1,8-cineole
- Chemical class
- Monoterpenoid ether, C10H18O
- Main source
- Eucalyptus oil: 63.1% of one Eucalyptus globulus oil analysed in 2023
- In cannabis
- A minor terpene in some varieties, not one of the main ones
- In skincare
- Studied as a skin penetration enhancer in topical formulations
What is eucalyptol?
Eucalyptol is a terpene, one of the aromatic compounds plants produce in their essential oils. Chemists call it 1,8-cineole. Its formula is C10H18O, and unlike most terpenes it contains an oxygen atom, bridging a ring (PubChem). That makes it a monoterpenoid rather than a plain hydrocarbon terpene like limonene.
It smells cool, fresh and slightly camphor-like, the scent most people know from eucalyptus. The terpene alcohol borneol also has a camphor-like smell.
Where is eucalyptol found?
The richest source is eucalyptus. In a 2023 analysis of Eucalyptus globulus essential oil, 1,8-cineole made up 63.1% of the oil, followed by p-cymene, α-pinene and limonene (Čmiková et al., 2023).
A 2021 review notes that eucalyptol is mostly extracted from plant essential oils, and that it occurs in many species (Cai et al., 2021).
Is eucalyptol found in cannabis?
Yes, in some varieties, but usually in small amounts. In a study of essential oil from Italian hemp, the main constituents were β-myrcene, limonene, β-caryophyllene and α-humulene; eucalyptol was not among them (Ovidi et al., 2022). A 2024 review of the entourage effect in medicinal cannabis includes eucalyptol among the cannabis terpenes it covers (André et al., 2024).
Terpene content varies between varieties and batches, so only a lab analysis shows what a given sample contains. Read more in What are terpenes?
Eucalyptol vs pinene vs limonene: what is the difference?
| Feature | Eucalyptol | α-Pinene | Limonene |
|---|---|---|---|
| Formula | C10H18O | C10H16 | C10H16 |
| Type | Monoterpenoid (contains oxygen) | Monoterpene hydrocarbon | Monoterpene hydrocarbon |
| Smell | Cool, fresh, camphor-like | Pine, resinous | Citrus |
| In eucalyptus oil (2023 analysis) | 63.1% | 7.3% | 6.9% |
Sources for the table: PubChem; Čmiková et al., 2023. See also our guide to pinene.
What does research on eucalyptol show?
Eucalyptol has been studied a great deal, mostly in cells and animals. A 2021 review summarises lab research on anti-inflammatory and antioxidant activity, and notes that few formulations exist to improve its stability and bioavailability (Cai et al., 2021).
For skincare, the most relevant research concerns the skin barrier. A 2024 review describes 1,8-cineole as a chemical penetration enhancer: in topical formulations, it can help other ingredients pass through the outer layer of the skin (Dao et al., 2024).
On the entourage effect, the 2024 review concluded that any enhancement of cannabinoids by terpenes remains unproven and needs clinical trials (André et al., 2024). Our guide to the entourage effect covers the debate.
From our production
We keep the hemp's natural terpenes in our oils; many people underestimate terpenes and assume only the cannabinoids matter.
— Robin Roy Krigslund-Hansen, co-founder and CEO
Frequently asked questions
What is eucalyptol?
Eucalyptol, or 1,8-cineole, is a monoterpenoid with a cool, fresh smell. It is the main component of eucalyptus oil and occurs in many other aromatic plants.
Is eucalyptol the same as eucalyptus oil?
No. Eucalyptol is one compound; eucalyptus oil is a mixture. In one 2023 analysis of Eucalyptus globulus oil, eucalyptol made up 63.1%, with p-cymene, α-pinene and limonene among the rest.
Does cannabis contain eucalyptol?
Some varieties do, usually as a minor terpene. In a study of Italian hemp essential oil, the main terpenes were myrcene, limonene, caryophyllene and humulene.
Why is eucalyptol used in skincare?
Mainly for its fresh scent. It has also been studied as a penetration enhancer that helps other ingredients pass through the outer layer of the skin.
Does eucalyptol add to the entourage effect?
That is not proven. A 2024 review found that enhancement of cannabinoids by terpenes, including eucalyptol, remains unproven and needs clinical trials.
This article summarises published research. It is not medical advice. Formula Swiss CBD oils are sold as cosmetics for use on the skin. They are not food supplements or medicines and are not intended to diagnose, treat, cure or prevent any disease.
Last reviewed:
Sources
- Čmiková N, Galovičová L, Schwarzová M, et al. Chemical composition and biological activities of Eucalyptus globulus essential oil. Plants (Basel) 2023;12(5):1076. doi:10.3390/plants12051076
- Cai ZM, Peng JQ, Chen Y, et al. 1,8-Cineole: a review of source, biological activities, and application. J Asian Nat Prod Res 2021;23(10):938–954. doi:10.1080/10286020.2020.1839432
- Dao L, Dong Y, Song L, Sa C. The fate of 1,8-cineole as a chemical penetrant: a review. Curr Drug Deliv 2024;21(5):697–708. doi:10.2174/1567201820666230509101602
- Ovidi E, Laghezza Masci V, Taddei AR, et al. Hemp (Cannabis sativa L., Kompolti cv.) and hop (Humulus lupulus L., Chinook cv.) essential oil and hydrolate: HS-GC-MS chemical investigation and apoptotic activity evaluation. Pharmaceuticals (Basel) 2022;15(8):976. doi:10.3390/ph15080976
- André R, Gomes AP, Pereira-Leite C, et al. The entourage effect in cannabis medicinal products: a comprehensive review. Pharmaceuticals (Basel) 2024;17(11):1543. doi:10.3390/ph17111543
- PubChem. Eucalyptol (CID 2758); α-Pinene (CID 6654); Limonene (CID 22311). National Library of Medicine
